There is a simple explanation. You can't..
In the "practice area" you can only select a hole and play it and you can't go to the next hole.
I know it's not that obvious and I wasn't sure how to do it any other way.
The practice area and the tutorial-course are mostly there for you to try the game and of course I want people to play full 18-holes. That's what it's all about, keeping focus for 18 holes even if things doesn't play out as planed. :)
It's worth to mention that stats are only saved on the two main courses and only if you play all 18 holes.
I hope that gives some clarity!