You can get free basic current account opened from most of the bank in Belfast.
You need to book appointment with bank (either through call center/online or visiting branch itself). They will ask for identity (your passport, visa) and address proof ( Utility bills, rent agreement, Overseas bank statement in original etc). Every bank has own list of documents which can be accepted. Please check the bank while booking your appointment.
With new digital banking it's possible to open your bank account before coming to the UK or as soon as you landed here. These banks are operated without any branches and you can apply online.
Some popular Digital banks are Monzo, Revolut.
You can download app, register online and upload your documents (passport/visa-BRP card/driving license) through the app. You can sort code and account number which is required to get your salary or overseas money transferred. You can also apply for debit card from the app.
ATM withdrawal is free only from Bank operated ATM machines. There are few third party ATM machines also from where you can withdraw cash with nominal charges. The currency used is Pound Sterling (£).