Here's what you should do
The first - and in most cases, the only - step is to download all your transactions from BTCC and import them to Koinly. There are a couple of ways you can do that:
- BTCC does not have any API, so you will need to download your CSV files from their web interface and upload them into Koinly manually.
- If you only have a few transactions and the above method(s) are not possible for you, you can even add the transactions one by one through Koinly's web interface.
Note that if you want to import CSV files, you have to make sure to import your deposits/withdrawals and trades for ALL years !
That's pretty much it. The only other thing to keep in mind is to tag your airdrops/forks so they appear as Income on your final cryptocurrency tax forms!