The first step is to download all your transaction data from heat wallet and import it into Koinly. There are a few ways you can do this:
Note that if you decide to use CSV files, you need to make sure to import your deposits/withdrawals and trades for ALL previous years - 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 cryptocurrency tax documents!