This video explains Field Extraction Rules (FERs), benefits of using FERs, and the best practices to be followed while creating the FERs.

For more details on FERs, refer to the Sumo Logic documentation here:
Best practices on Field Naming Conventions: https://help.sumologic.com/Manage/Field-Extractions/01-Field-Naming-Convention
Limitations on field extractions: https://help.sumologic.com/Manage/Field-Extractions#Limitations