Checkbilliard checks your skills and analyze them. These are different skills and we use them as key factors – Speed and straightness for example.
Depending on the results in the tests series the skill sreen shows you with thumbs if the skill is OK (green thumb) or if you have a deficit here (red thumb). The green thumb you need not have to practise – but of course you are allowed to do that. The red thumb you have to practise in ascending order to improve your deficits. Whereby the 3 lowest deficits are to be practises first (unless there are 3), if you resolves the first red thumb the 4th red thumb will be unlocked, etc.