To access your seller data the AMZ Performance Tool needs to be connected to Amazon's MWS API. This requires two things:
Your Seller ID
You can create the MWS-Auth-Token on https://developer.amazonservices.co.uk.
Attention: Create a NEW token. Please do NOT copy the token of another application, it will cause problems.
To do so, click on the "Sign up or manage Amazon MWS" button marked in the above screenshot. Now you have to log into your Seller Central and click on this button:
You will be redirected to this web form. Please fill this out exactly as shown below in the screenshot, click on "Next" and accept the conditions.
Application Name: ShopDoc
Application`s Developer Account Number: 1240-7264-2509
After receiving your token and Seller ID, you can insert these two parameters directly into the tool.