Login to your BitMax account, hover your username on top right and select API Settings. Then click New API key (in case the button is not active, make sure to complete Account Verification first).
Make sure to give permission to View, name your API with any name you'd like to (ex. CoinStats BitMax), input your email verification code and 2FA. Then click Generate API Key.
You will see a screen like below with your Public and API Secret Keys.
Please make sure to copy/paste your Secret Key to a safe place, as it will only be displayed at the time it is created. If you lose this key, you will need to delete your API and set up a new one.
Now go to CoinStats app Portfolio tab, swipe far to the right and click Connect Exchange.
Select BitMax from the list and paste your API Key and API Secret.
After clicking Submit you will see your BitMax portfolio synced with the CoinStats app.
Refer to support in case of further questions. Hope you'll enjoy!