Login to your Kraken account and click Settings.
Then select API.
Click on Generate New Key button.
After clicking Generate New Key, make sure to give permission for Query Funds.
Click on Generate Key button.
After the message "New API key generated successfully" you can add them in CoinStats.
Please also note that in security settings two-factor authentication for API keys must be set to "No method" in order to be able to sync with CoinStats.
Now go to CoinStats app Portfolio tab, swipe far to the right and click Connect Exchange.
Click QR and scan the QR code presented by Kraken or copy/past your API Key and API Secret Manually and press Submit.
After that will see your Kraken portfolio synced with the CoinStats app.
Refer to support in case of further questions. Hope you'll enjoy!