Morty knows he shouldn't be screwing around with multidimensional shit. It's dangerous, it's impractical, it's blah blah blah. But it's a potential key to unlimited energy, how does nobody see that? He's built a dimensional siphon (it kind of looks like a cardboard box with a funnel and a TI-84 taped to it, but it damn well works), keyed in the dimensional coordinates to a random plane, and by God he's going to use it.
He flips the switch and waits for the energy bar to fill up.
It does! It fills up very rapidly. Then it explodes, along with the box. There's rather more smoke than there should be, and once the smoke clears someone is standing there.
"Whoops?" Morty says faintly.
"You'd know better than I would! Which of these is easiest to learn to use from a cold start?"
Morty looks through the phones, then picks a model. "None of them are going to be super easy, but this one takes voice commands, so I think it'll make more sense."
"Cool." She baskets it. "I guess I'll have to come back for textbooks later so it's okay if I've forgotten something."
And Morty shows her to Melville so she can drop off her purchases in her dorm room!
"I'm gonna have to leave you here - the Melville housemother or fixer's gonna take over now that you're in their territory. It was nice meeting you! Even given the, uh, circumstances."
"You're welcome and I will hopefully never do it again because that was absurdly lucky!"
He makes his way back to Twain.
And she lugs her laundry basket full of stuff to her room. If her ID card has her room number.
"I cannot! You are welcome to carry my basket." She hands it over. "Do you know where my room is?"
"Hi, Alice!" Bella shakes her hand. "I'm from another plane and was accidentally summoned here and am staying because my plane is bad!"
"Thanks! Oh - one thing - do you know who I talk to about whether I can wear my magic boots during the martial arts class?"
E-mail is - oh, a-mail, okay. "My plane doesn't have computers."
"That's my plan. I'm hoping it's a straightforward translation from crystal balls. And how do I pick and sign up for classes?"