The first - and in most cases the only - step is to download all your transaction data from dragonex and import them to Koinly. There are a couple of ways you can do that:
If you decide to import CSV files, you must make sure to import your deposits/withdrawals and trades for ALL previous years !
That's it. Don't forget to tag your airdrops/forks so they show up as Income on your final cryptocurrency tax forms!