It's minigolf, you know how to play minigolf.

How to Play Minigolf

Use the mouse to aim.
Mouse cursor distance to ball determines power.
Click to putt.

Click to use the menu and advance through score screens, too, it's all clicking.

The lower your score the better, but now I'm being patronising.

Thanks to Bilby (bilbyfactor.itch.io) for making some levels.
Flan-Flan helped too, but he isn't on itch.io so w/e.