The first humans sin (shown through the figurative language of Genesis as "eating the fruit of the tree of knowledge of good and evil") and screw up the world. God, not wanting to give up on us, guides a chosen people (first a couple, then a family, a tribe, nation, kingdom) until it is time to send the Messiah. For us men and for our salvation, Jesus, the second person of the Holy Trinity, came down from heaven, and by the Holy Spirit was incarnate of the Virgin Mary, and became man.
He lives a quiet life until his adulthood, when he begins his ministry. Jesus gathers his disciples (12 were chosen to be closer. His Apostles) and travels the area, teaching, standing up to hypocritical pharisees, and performing miracles. He loses many followers when he tells them they must eat his flesh and drink his blood, but the Apostles stay.
By the end of his ministry, the Jewish authorities want him dead. He gathered with the twelve in an upper room (traditionally, the home of Mark the Evangelist). Jesus washes their feet (a task normally given to slaves). With this act, he is showing them how to live once he is gone: serving others. In addition, ritual washing was important to the Jewish people. The priests would wash their hands and feet before approaching the altar, so this could be interpreted as a priestly act.
They move onto the Passover meal. It proceeds normally at first. However, Jesus changes the ritual before it is over. Breaking and blessing the bread, he gave it to the Apostles, saying "This is my Body". In a similar way, he took the cup, blessed it, and gave it to them, saying "This is my Blood." He instructs them to repeat the act in memory of him.
After the meal, he went to pray in a garden. The power trio of Apostles: Peter, James (the greater), and John were to keep watch, but they kept sleeping. Judas, one of the apostles, betrayed Jesus and brought the authorities to arrest him. Peter struck at one of the guards with his sword, but Jesus rebuked him and healed the guard.
Jesus was tried and found guilty of blasphemy. For our sake, he was tortured and sentenced to death through a brutal execution: crucifixion. He suffered death and was buried. A few women wished to prepare his body for burial, but they didn't have time. It was almost the Sabbath, and no work could be done. They returned on Sunday and found an empty tomb. He had risen!
Over the next few weeks, he appeared to his disciples. Preparing them for what was to come and promising they would be guided by "the Paraclete". Jesus ascended into heaven. The apostles were frightened and didn't know what to do, but the Holy Spirit gave them the grace they needed to go preaching about the Christ. That was the first day of his Church, which is still around today.
Last night was Holy Thursday, the Mass celebrating the Last Supper. That Mass...the celebration of the first Mass...begins the Easter Triduum. Today, the only day with no Mass, will be Veneration of the Cross. Tomorrow night, the Easter Vigil. I, along with many others, will celebrate the Lord's sacrifice and resurrection with sacraments he instituted nearly 2000 years ago.
You ask what Easter means? It means that despite our fallen state, God did not abandon us. He suffered a brutal death for us. He defeated death for us. He built a Church through which we are given incredible graces.
It's love.