You needed extra training for Quirk and combat skills, so your teachers, Aizawa and Present Mic decided to help you (Mic forced Aizawa into this.). Present Mic told you to meet them in the training ground. More specifically, Ground Omega which is a big forest. You head down to Ground Omega. You are greeted to an enthusiastic Mic and a tired Aizawa.

"Yamada, they're here," Aizawa says to Mic.

"Listener! You're finally here! What took you so long?" Present Mic asks.