Help Using Drumset Notation

I am struggling to use the drum set notation to write out relatively simple exercises with ride cymbal, snare, and bass drum. Despite consulting the handbook and searching online resources, despite trying to use the instructions given in various places for managing chords (which as I understand it, are essentially what the drum set notation creates with the various staff lines for drum set elements, I find that all my attempts to add snare drum comping hits using Shift below a steady ride cymbal pattern, inevitably impact and change the steady ride cymbal rhythm on an upper staff line. Even with a simple quarter note rhythm in the ride cymbal, trying to add a half-note rest on the first quarter note on the snare drum staff line, selecting the first quarter note and using Shift plus A and also clicking the rest sign, removes or changes the ride cymbal quarter note in one way or another.
Is there anyone out there who would be willing to help me out, ideally with a zoom call? I think I brief live discussion of how to do what I am trying to do would be enormously helpful. I am even willing to pay for this "lesson" if the cost is reasonable! I know this can't be as difficult as it has become for me, and I would be very grateful for help in getting this sorted out.