CAP 739: Flight Data Monitoring | Publications | CAA
This should provide you with the basic understanding of the FDM/FOQA requirement.
Siince you are going for a position where you will be providing analysis services to airlines through a third party, make sure you read up on the company (Teledyne Controls) and their FDM software (AirFASE).
Let me know if you need any further info. All the best