Found an overhead wall training demonstration on instagram which is quite helpful.
Things to note.
1. the wall encourages the elbow to come up higher. Many people have their elbow only as high as the shoulder level.
2. Try not to fall away from the wall to far on follow through.
3. unfortunately the right foot going forward is not demonstrated. If adding it in, the wall makes the right foot go forward instead of swinging out in a curve to the right which many people do and are unaware of.