Understanding the FAA Rules Regulations is mostly a matter of becoming familiar with the specific regulations that apply to Unmanned Aircraft operations. That begins with 14 CFR § Part 107 which lists the requirements, restrictions and limitations, the certification process, definitions and safety measures. For most people, this can be the most difficult part, but in reality, it comes down to simply being familiar with the regulations.
There are other regulations that apply to unmanned aircraft, including recent changes which provide for night operations, operations over people and implementation of Remote ID requirements. Drone operators must be aware of restricted airspace and altitude limitations to avoid potential conflict with manned aircraft.
This book takes you step by step through the material you need to know, but in a way that is easy to follow and build an understanding.