The first step is to download all your transaction data from coinomi and import it into Koinly. There are a couple of ways you can do this:
If you decide to import CSV files, you must make sure to import your deposits/withdrawals and trades for ALL previous years - not just the current one!
That's it. The only other thing to keep in mind is to tag your airdrops/forks so they appear as Income on your generated crypto tax documents!