The first and usually only step is to download all your data from Allbit and import them into Koinly. There are a couple of ways you can do that:
Note that if you decide to use CSV files, you have to make sure to import your deposits/withdrawals and trades for ALL years - not just the current one!
That's all you have to do. Don't forget to tag your airdrops/forks so they show up as Income on your generated cryptocurrency tax documents!