Login to your Cex.io account and select Profile from your username dropdown list on top right.
Then select API from the Account Settings.
Click on Generate key button.
After clicking Generate, it will show your Key and Secret. Please note that Secret will be hidden after you activate it.
Click on Activate button.
Action needed: Click the link in the email to activate API key.
After the message ''Your API key has beed activated'' you can add them in CoinStats
Now go to CoinStats app Portfolio tab, swipe far to the right and click Connect Exchange.
Select Cex.io from the list and paste your API Key and API Secret.
After clicking Submit you will see your Cex.io portfolio synced with the CoinStats app.
Refer to support in case of further questions. Hope you'll enjoy!