Taking a breath is the first act of our lives, and our bodies just know how to move to take in air for our survival. But through inaccurate teaching and trauma, we “forget” how to breathe by trying to move from places in our bodies that don’t accomplish the goal OR by deliberately inhibiting movements from the parts that do bring air into our lungs. Here are some images and links to videos that give us some information to relearn how to breathe as nature intended.
This image shows all parts of the body involved in respiration:

This drawing from the classic Gray’s Anatomy shows the extent of the lungs in the context of the rib structure:

Notice that the upper tip of the lungs extend above the collar bone.
Another Gray’s drawing shows the view of the lungs from the side:

This video gives a quick overview of respiration:
This animated video offers a more in-depth discussion: Respiratory System of the Human Body – How the Lungs Work! (Animation)
And this is my favorite video of all, showing a dynamic MRI image of breathing. Notice at the edges of the thorax how the ribs are moving. Real time MRI of Breathing
This list gives you a starting point to do your own explorations about breathing.
Breathe well, live long, and prosper!