Accessing filesystem to modify Safepoint to exclude files/folders

In some cases, my MBL system is the main filesystem (e.g. pictures, videos, personal business info) and in some cases, it is used to backup multiple personal computers via WD SmartWare.  So, I want to use SafePoint to backup only portions of the system to a second WD system so that I can store a periodic backup offsite (e.g. quarterly). 

The posting noted above discusses how to do this.  Seems relatively simple (except for a non-Linux individual).

I would appreciate a step-by-step process from a Linux expert.