You will find that this topic has been thoroughly explored and that there is not much meat left on the bone.
But lets be that remaining meat for a moment.
Know that you have discovered the 2 main things to do with Breathing.
1. Breathe through the nose, this is very important for many reasons. 2. Try to breathe in 6 second intervals. 6 second inhale, 6 second exhale.
This is hard to do, but know every try is moving you closer to what needs to be performed. This is how you proceed forward, spend 5 minutes each day practicing the long breaths while standing.