The ten minutes static push up can seem intimidating and at first you may feel a lot of tension building as you fight the tension instead of releasing it with the breath. Consider this way to reaching the mark:
Place a timer for ten minutes and start it. For every minute keep the static push up for thirty breaths working to stay relaxed using the exhale to out extra tension and the inhale to draw it from the body. Use the rest of the minute to move your fists around as you sit with a straight back and getting a feel of how a heavy fist feels. As time goes by increase the number of breaths until you fill the entire ten minutes but come back to this drill from time to time to get the feel of the moving heavy fist. Watch your wrist alignment and tension in the palm and fingers.
It’s ok to smile.