@Miri *********
you need a long-term visa to get a bank account. You need a bank account to get a long term visa. Welcome to Thailand 🙂
Personally I visited about 3 or 4 branches of bkk bank to get my first bank account. They required a notarized copy of my passport from the US embassy as well as other documentation. So that took weeks to sort out.
Bringing a native Thai with you can help as well.
And then there are agents who can get this done for you, for a fee.