Hi Chrissy. I time my breathing with my steps. I start my breathing on a 4 count. Inhale for 4 steps (deep breathing), exhale for 4 steps. A few minutes in I go to 3 steps in, 3 steps out. I usually settle in around 3 in, 2 out; but go to 2 x 2 if/when needed. But whenever possible, I move back up to 3x3 or 4x4. Everyone is different, so I hope you find what works best for you. The best advice I have is to make sure you are taking deep breathes, from the stomach not the chest.
Happy running!