The first - and in most cases, the only - step is to download all your transactions from Coindeal and upload them into Koinly. There are a few ways you can do this:
If you want to use CSV files, you need to make sure to import your deposits/withdrawals and trades for ALL previous years - not just the current one!
That's pretty much it. The only other thing to keep in mind is to tag your airdrops/forks so they show up as Income on your generated crypto tax forms!