This information is supplied for you by PowerReviews.
PowerReviews will assign this information to you when you sign up for their service. The Merchant ID and Group numbers are actually contained within the various scripting codes PowerReviews denotes for your account. To retrieve them:
- Log into your PowerReviews Dashboard at http://dashboard.powerreviews.com/
- Hover your mouse cursor over the “Configuration” menu and click “Get Code”
- In the initialization code section, you will see a URL written as “http://cdn.powerreviews.com/aux/[number]/[number]/css/express.css”
The first number is your Merchant ID and the second Number is your Merchant Group. Copy these and apply them to your PowerReviews settings in the Store Modules section.