Although, as has been said, there are no rules for putting areas, they are intended to be a practice area. In order to make the practice worthwhile there is no point in only hitting one ball on each hole. You should be taking at least three (more if it is not crowded).
Competitions should not be played unless they are not interfering with other players practice.
There is no reason to play the holes in order if you are practicing and the area is busy.
In fact if you think about it, the only reason (except if there is a slope on the area) to move to another hole is to save time walking back to the start point for that hole when you have got all the balls in the hole. Just step across to the next.