Applying for accommodation?

In my last year of college and gotten my uni offers but I didn't realise you had to apply for accommodation now. Just have a few questions:

1. Are you only allowed to apply for accommodation at your 1st choice? What is you don't get in there but you get the grades for your 2nd choice?

2. I've also heard that some places make you put down a deposit. What if you don't get the grades to go, would you get the money back?

3. In most cases do you apply through the uni website?

Thanks for any help!

1) You need to check the details as it varies by university. Some guarentee accomodation for insurance students, some say apply anyway and we will try and find you a room if you end up at our uni, some say sorry if you go here you'll have to find a house.
2) Most places don't make you put down a deposit until after results day when your place is confirmed. Nottingham Trent asked for one before but they said they would refund it if you didn't get in
3) Yes