Forensics

Hey,
Not seeking direct help for the moment, I just want to know if there’s any particular material I should go over/stuff I need to read about to get an idea of what to do. For the moment, >> all I did was find the file names using some tools and Im guessing (could be wrong) that the data of the file is somewhere in the disk image but how do I get the data that matches the file Im looking for . Should I read about smth first or just stick with the classic “Google whenever feel like I need smth” ? Thanks in advance