The first and usually only step is to download all your transactions from c2cx and import it into Koinly. There are a few ways you can do that:
Note that if you want to use CSV files, you need to make sure to import your deposits/withdrawals and trades for ALL years and 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 cryptocurrency tax reports!