Login to your Bitstamp account, and navigate to your API keys by selecting the menu for Security then API Access.
Please take note of your Customer ID in the upper right hand corner of the screen here. This is the Customer ID that must be entered into your CoinStats app when you are linking your BitStamp account.
Make sure to give permission to Account Balance and click on Generate Key.
You will now see a page which will show your API Key and Secret.
You will not be able to see your Secret key again once navigating away from this page. Please copy it to a secure location at this time.
Click Activate and follow the link sent to your email.
Now go to CoinStats app Portfolio tab, swipe far to the right and click Connect Exchange.
Select Bitstamp from the list and paste your API Key, API Secret and Customer ID.
After clicking Submit you will see your Bitstamp portfolio synced with the CoinStats app.
Refer to support in case of further questions. Hope you'll enjoy!