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