It's a parody, there's not much to translate.

First task is to demonstrate unity by drawing part of a story without knowing how far your predecessor got. Momorin skips a few steps, Gollina goes backwards and Catherine is off as well. So they end up in the stink box.

Idols can sing anything, including stuff made up on the spot by some idiot.

Improv drama. Saaya has to confess, guy obviously can't go out with a girl who can't do cartwheels, so she tries. Momorin misreads the extra-long words on the cue cards.

Extra-wasabi sushi is supposed to give you an edge for the final scene, but the zombie wasn't in the script so Catherine runs scared.

Yet they get a pass from the evil instructor and can continue to complete their idolness.