Process Configuration records contain several pieces of information for a table you want to mine.  You set what fields you want to use for Root Cause Analysis in that record.  You would also configure the Cluster definition and Finding Definitions in that record.  https://docs.servicenow.com/bundle/vancouver-now-intelligence/page/administer/process-mining/task/cr.... 

You can find the Process Configuration module in the left hand navigation under the Process Mining application.  

Here is an example of the record you'll be configuring 

We don't have a specific Academy session just on Process Configuration records but we do touch on them in this session about Process MIning for External Data https://www.servicenow.com/community/process-mining-blog/process-mining-academy-19-process-mining-fo...

Hope this helps.