FFT is a textbook example of schizophrenic difficulty. Some battles are quite simple while some as early as the Slums of Dorter will wear your ass as a hat. That said, it's one of my all-time favourites, practically founding the isometric turn-based strategy genre in North America with its unique style and plot. The original's tutorial was the poorest-translated part of a very poorly-translated game, so count your blessings and try again. I promise it's a great experience once you learn the ropes.
I find it unlikely that random encounter you described had more than 3 Chocobos- some don't even have 5 enemies to match your 5. In that situation among others, the idea is to focus down your targets one by one. Don't chase them, let them come to you. Most monsters have a physical Counter ability to make up for their inferior stats compared to human characters. If you plan things out you can get a surround to stop a Chocobo from escaping. Even better, it may be stupid enough to use Choco Cure to keep itself alive, thus healing all of your characters. Remember you can check an enemy's range by pressing X with the cursor over them, and check the turn order by pressing right while selecting a special attack (at least in the original). It's generally good to have at least one long-range attacker to lure the enemy out of their covered positions, even if at the start you're limited to Throw Stone or Archers.
Also if you feel the need to grind levels, the fastest way I've found is simply to spare one enemy at the end of a random fight and just have everyone spam Accumulate or some other buff. In the case of monsters, they'll usually run cowering to a far corner once they're in critical HP, leaving you to gain as much power as you need.
