Go to the casino's homepage and click "Deposit' button. Here is an example from Pronto casino:
Tip: Each casino might have different names for the button: 'Play', 'Deposit', 'Deposit&Play' etc.
On the deposit window choose the amount you wish to start with and payment vendor (if applicable) like Trustly, Swish, Brite or others.
Tip: there are usually predefined amounts in the deposit box but you can set your own
Choose the bank where you have an account from the dropdown list. Usually the most popular banks are at the top.
Tip: if you can't find your bank try using the search bar to speed up the process
To complete the top up, use your bank ID information to verify the transaction
Tip: there are several ways to use Bank ID verification, e.g. Making a deposit on your laptop you can use tour mobile for verification.
Your money should be in your account by now. You can start playing at the casino right away