How can I qualify for BAH?

I'm National Guard and I will be going overseas for quite some time, and I just have some questions about how to qualify for BAH and no one in my unit seems to know completely.
As far as I know, I need to get a renter agreement, take it to the bank to get it signed, and then submit it to my unit, but I just want some clarification to make sure I'm doing everything correctly.
any help would be appreciated. thank you!