Breathing can be complicated. Below is one of my favorite videos of how the diaphragm muscle works (that’s the major muscle we use to breath).
The second video is how to breath using your diaphragm. As you progress with your breathing, you will want the breath to flow in and out of your nose and your belly won’t expand as much. When first using your diaphragm, I find it highly beneficial to stretch the core from the inside out to be able to gain the range of motion in the diaphragm that had been lost from years of breathing by lifting the shoulders up. More in depth meditations, exercises and stretches for the diaphragm can be found in the first week of the Voyage to HEAL. You’re welcome to just purchase that week as well. Here is the link: Voyage to HEAL Diaphragmatic Breathing