You jelly.

Warning End of Evangelion is batshit insane and will cause you to make you question yourself when you see the Asuka and Shinji in the hospital part.

Also to help with the confusion you will have:

 Spoiler

Human A.T. fields are what constrains a soul to their respective body. Without it your body liquifies and your soul is set free. An anti A.T. field seems to be just a large explosion which can destroy AT fields but only when the Third Impact happens. Without the Third Impact its just a big explosion (as we have seen when angels self-destruct). The Human Instrumentality Project is a plan conceived by SEELE (a bit like the G8 council but way more powerful) and they placed Ikari in-charge. It is where everybody's soul is detached from their body by making Ayanami Rei (a genetic modification of Lilith (the big white person in the Central Dogma)) enter Lilith (an angel from which humanity descends (all angels are supposedly alternate forms of mankind and would have taken one of these forms if evolution took a different turn)). This meeting of Ayanami and Lilith, called the Third Impact, will destroy everybody's AT but it also requires Eva Unit 01 to work as an amplifier or medium. Essentially SEELE wants everybody's souls to unite so that everybody is happy or whatever and by doing this they have reentered the garden of Eden. However Ikari wants to use Adam to initialize the Third Impact. I dont understand what happens if either Adam or Lilith is used but in the film they use both (remember Adam is the fetus in Ikari's hand). Adam blew himself up 15 years earlier in the Second Impact turning himself into a fertilized egg cell and this was inserted into Ikari's hand.

And that doesn't even scratch the surface on what you need to know to understand the series.

Good luck newcomers!

 Spoiler

I'm so f'ucked up.

Lulz.

And to touch on a few things Derosis said that are partially true.

 Spoiler

Rei Ayanami is considered a genetic modification of Lillith but in reality is a clone of Yui Ikari, Shinji's dead mother. From the beginning, SEELE put Gendo in charge of the Project (HIP) but right off the bat Gendo planned to take control of the situation on his own and developed Rei, thought to be his "daughter" by his co-workers when really she was just going to be used so he could be the dictator of said project, not SEELE.

The Human Instrumentality Project can be succeeded by two or three probable methods I believe. Two being SEELE's and one being Gendo's personal plan. One of SEELE's is to combine Lillith, Lance of Longinus, and an Evangelion's S2 engine to fully complete a cycle of the project. Gendo's method is to combine Lillith, Adam, and the soul of Lillith which is later discovered as being Rei. Both these can cause the Third Impact and SEELE intended to use all of their tools at the right time because they felt that evolution has reached it's peak in the world, however Gendo just wanted to reign supreme.