If you don't know the rules, why don't you play another game you and your group haven't tried before? I haven't really played D&D since 3.x ed ... and I'm content with that because I play other games and every version of D&D is rife with new stuff.
People can say that D&Dis easy, but it's pretty convoluted and bloated. Honestly, the thing that will fuck you up the most is encounters and how spells work. Because nearly every player will have some permutation of spell-like abilities that you'll have to learn. So if you have any time to learn something really thoroughly it's how magic works.
More people should play Torg: Roleplaying the Possibility Wars ... Torg is amazing. You just need a d20 and the decks of cards.
It's easier to games master because the scenes run more like scripts and the actions are driven more by cards ... and it feels thematic AF. Like it works so fucking well. Torg is the closest game to ever feel like an actual movie playing out.
All you have to do is familiarize yourself with one place, and with a smallchart it tells you everything you need to know about how that part of the world functions. You write a 'loose script' of events and places. It gives you largely pre-prepared characters for everyone to just jump into.
Seriously, Torg should be your introduction to GMing ... not D&D.
With a game of Torg you and your players will actually do stuff regardless of your experience bracket. And no one will rules lawyer you and your worldbuilding into the ground. And because the GM is merely treated as a player with cards, and death can happen quite quickly, but because there's a low buy in bringing in new characters ... no one will blame you for simply 'playing the cards and setting the scene' ...
This is just 'how thescene is playing out' ...
Seriously, even death feels amazing in this game.
Like my 'National Hero' character was dealt the Martyr card which I saved until we met the big bad of the mini-campaign. The Martyr card allows you to basically roleplay out a scene where your character, if possible, can throw a wrench into the worksof any bad guy at thecost of their character... and it feels precisely this epic ...
Guaranteed, if a player has worked hard to manufacture the possibility of roleplaying of that card they quietly held onto for *multiple* sessions... and has taken the time to think about how to roleplay out what they're going to do as their final deed... everyone will be grinning.
So that's my suggestion. Start with something easier, something that works with creativity more than hard dice rolling of 101 different integers, something that chances are your players haven't already played, that allows pre-generation plus customization along the way. Something that also doesn't penalize newbies in favour of the experienced...
Plus it's simply a cheaper game... So my suggestion of how to GM a game of D&D that you know nothing about? Don't GM D&D at all... pick something better constructed to work with your inexperience of GMing until you are actuslly familiar with D&D.
And Torg is probably the best game for that that has ever been constructed.
Basically the most difficult thing you will have to figure out in Torg as a GM is the 'Dramatic Scene' shift mechanics... but no other game will give you a more comprehensive understanding of GMing a scene than Torg will.
Moreover, and this is crucial--Torg will teach you what to do when you fuck up. A bullshit series of dice rolls can transform what was meant to be a difficult encounter to get that magical mcguffin into a cakewalk or a TPK ... and Torg avoids this expertly and teaches you how to rebalance and rescale on the fly without the players feeling like the GM is making it easier or harder on them, all while making the scene incredibly immersive and seamlessly blending it into the action.
Torg will teach you how to GM according to a multitude of different themes, from gothic horror, weird science, high fantasy, and gritty realistic urban settings, where and when to reward player interaction with those themes, and how to construct evolviung narratives and gamestates.
And once again ... despite all of this, it's a phenomenal game system on its own merits while also being cheaper than buying a whole bunch of D&D books, it has a lower barrier to entry, it's something your players likely haven't played before, and what it teaches you is applicable everywhere else in GMing.
I highly recommend Torg for your first time GMing ... even more so if you have no fucking idea of another game you're going into.
If you want to torture yourself, I can't stop you ... but if you're invested in making your group an actual thing--first impressions matter. And oh my God, does Torg leave a god damn impression. It is masterful roleplaying design at a pricepoint no one can argue with.
Basically the only downside to Torg is that there are cards involved ... so unless you want to sleeve them all, it does put a dampener on finger food your might want to bring or prepare for games night.
That being said I'm a damaged veteran of the board gaming scene and compulsively sleeve all my cards of every game I've ever gotten, so it depends on level of whether you want to spend an hour doing the Drama Deck and sleeving all of them ... I personally find sleeving cards therapeutic ... just mellow out to some music while doing so. There's a small amount of inexplicable meditation to sleeving cards. You get into the rhythm and it's like you're on total autopilot.
It is something to consider, however.
As a GM ... you will like Torg if you;
A: Read something like Lord of the Rings.
B: Want your roleplaying to emulate some of those scenes.
C: Want your sessions to have movie aspects of being self contained, and campaigns themselves being like Hollywood epics of a variety of genres. Pulp action, neo-noir, high fantasy, cyberpunk, gothic horror, and more.
The reality of D&D is;
A: Squabbling over alignment.
B: Whether Destruction is considered a instant death effect.
C: Stupidly complex combinations that make no sense as either RAW or RAI (Rules As Written, Rules as Intended)
Seriously, it's a game system where a player will argue something that causes 1 point of damage should be treated as dice or not ... and on that basis alone fucking break the game.
I say that as a person who likes D&D 3.x ... it really isn't a very good introduction to tabletop roleplaying. D&D has and will always be an incredibly bitty mess of rules, dealing with players, and having to nebulously enforce some kind of egalitarianism of buils otherwise players will go too far with the most zaniestly stupid of builds that simply defies capacity to effectively challenge.
Like my half-nymph human bard/barbarian/warblade charisma-based melee build at ECL 9 that delivers a Will save DC22 fear effect check as soon as I attack something, that auto esclates to frightened or panicked any enemy within 30' that sees me attack something.... all while dealing +5 hit and damage to every player's attacks (including my own) and auto full attack on charge, with a free movement that with my shoes of battledancing + my falling charge feat allows me to use me charisma to hit and to melee damage ...
And if you think that's kind of bad enough, just wait until you give me an item I can conjure Sirine's Grace at level 12+ before a fight by hate pointing Use Magic Device and have over 40 AC by level 12, most of which generated by Improved Combat Expertise, native dex, non-magic abilities, and other undispellable abilities.
Literal AC tank with still about half as much HP as that raging barbarian also on the team and virtually untouchable beyond AoE spells that at best I'll still only take half damage on ... let me buy a ring of evasion and not even then.
And this is the thing ... that's not even that broken ... but if I'm playing in a group of new players to D&D, they'll certainly be questioning whether their vanilla barbarian or ranger build is all that pointful compared to my character I bring to the group.
And this is precisely why D&D is not newbie GM friendly ...
Because while an experienced player can teach other players and perhaps assist building their characters to however they imagine them to want to be ...that experiwenced player can't coach the GM.
