Click a tower's button to buy it (or press 1, 2, or 3) , then Click somewhere to place it (or Right-Click to cancel)
Click "Next Wave" or press Spacebar to start the next enemy wave
Press F to toggle fullscreen
This is one of the most basic / beginner-friendly tower defense (TD) games you can make
(This game works on mobile / touch devices)
Ask here if you have questions:
https://community.flowlab.io/t/super-simple-td-w-20-objects-tower-defense-example/47218