Activity diagram multy-choice at the beginning

I am working on my first activity diagram and I really got stuck. To be more specific its about Sudoku game. Well what my problem is, let's say that user at the beginning has option to choose game difficulty.

For example hard easy and medium difficulty. So the main problem is that I have no idea how to start. I tried something so far and I am gonna link it down below.

If someone could help I would appreciate that.

You should use a decision node like this:

The labels in square brackets denote a guard which shows the user choice and where the control flow will continue.