[It's not like Ochako is just going to hand him the net and tell him to go wild. As soon as they're down by the water, she grabs the long string attached to the net, gives the whole thing a good shake, and holds it out for him to take.]

Loop this part around your wrist, okay? Then you need to grab the bottom of the net—that's the part with the weights—and swing the whole thing over into the deepest part of the water. As soon as it hits the bottom, you yank it right back up!

[She looks up at him expectantly, confident that he caught that whole spiel. This isn't rocket science.]