The first and usually only step is to download all your data from Bitbns and upload it to Koinly. There are a few ways you can do that:
Note that if you decide to import CSV files, you have to make sure to import your deposits/withdrawals and trades for ALL years !
That's all you have to do. The only other thing to keep in mind is to tag your airdrops/forks so they show up as Income on your final cryptocurrency tax documents!