I am a beginner, My view builds a phone model, I don't know how to make the speaker part
First of all, good day. It is very easy to make any kind of holes in blender and can be done in many different ways like. But the easiest way of doing it is by either doing Shift+Ctrl+B (Done on vertices) or Ctrl+B (Done on edges). These "expands" the edge/vertices in a way. Ill leave you to do the rest, I hope this helped and experiment with these too!