The first - and in most cases the only - step is to download all your transactions from Neraex and import them to Koinly. There are a few ways you can do this:
If you want to use CSV files, you have to make sure to import your deposits/withdrawals and trades for ALL years !
That's pretty much it. Don't forget to tag your airdrops/forks so they show up as Income on your generated cryptocurrency tax documents!