There are two ways to make these adjustments. These days, most people will utilize an auto-calibration of some sort, i.e. Audyssey MultEQ or Yamaha’s YPAO. However, some entry level and older ...
Level matching your speakers isn’t a topic that gets talked about much these days. With auto-calibration systems like Audyssey MultEQ, Yamaha’s YPAO, Anthem’s ARC, etc., it’s generally done for you.