Either inhale and exhale through and out the mouth or inahle and exhale through and out the nose. Don't mix nose with mouth. One or the other. You need not do this perfectly. In short don't stop at the top of the breath or the bottom.
Breathing is one nonstop loop.
Your fingers spread slightly apart and not touching each other. The heal of your hand should be resting comfortably on the bridge of your nose. Parts of your palm should be gently covering over your eyebrows. The area your palm and fingers are covering is the major confluence of all the energy meridians flowing into the front of the brain. Simply take your left palm and lay it across the boney protuberence at the lower rear of your head.