After the Rite of Passage, you manage to enter the 104th Training Corps as a trainee alongside Mikasa Ackerman, Reiner Braun, Bertholdt Hoover, Annie Leonhart, Eren Yeager, Jean Kirstein, Connie Springer, Sasha Blouse, Krista Lenz, Armin Arlert and more. You will all learn to use the ODM gear and your blades as you train, and eventually you'll be able to fight actual titans when you graduate. Make sure to think for your decisions, because it can and will have consequences in the future.