The first - and in most cases, the only - step is to download all your transactions from C-Patex and import it into Koinly. There are a few ways you can do that:
If you want to import CSV files, you have to make sure to import your deposits/withdrawals and trades for ALL previous years and not just the current one!
That's it. The only other thing to be vary of is to tag your airdrops/forks so they show up as Income on your final crypto tax reports!