You must first watch the TV series, which has 26 episodes, and then watch a movie called "The End of Evangelion."
This way, you will be able to have access to the complete story that will allow you to understand the plot.
You can find these episodes on streaming services, especially those that are focused on providing Japanese animation both serially and feature-length.
If you want a more complete experience, you should try reading the manga, which presents the story without adaptations.
Manga can be found at comic book stores.
More information about manga at the link:
https://brainly.com/question/14619738