The chance of securing a loan from a Finnish bank depends on your employment status, income, the amount you wish to borrow, your residence status, your credit history and, if available, your sponsor.
Rates can vary significantly between different banks, so you should definitely shop around to see what is available. Once you have settled on a specific bank to apply to for the loan, you should contact them to arrange an interview. They will be able to explain issues concerning tax and which documents you will be required to submit.
If you wish to have your documents translated into English you should make this clear at the bank. It is advisable to have every single document translated into English rather than just the ‘most important’ ones.