Wave 01
As part of the tutorial, you will build a Wee Ninja hut on square 1, and upgrade that hut. When you fully take control of the game, you should build a Wee Ninja hut on square 2. Fast-forward to start the demons coming.

Wave 02
At the end of the wave build an Anti-Ninja hut on square 3.

Wave 03
Do nothing, you should be fine.

Wave 04
At the end of the wave build a Wee Ninja on square 4, and an Anti-Ninja on square 5.

Wave 05
Relax while your ninjas take care of business.

Wave 06
At the end of the wave upgrade both of your Anti-Ninja huts.

Wave 07
Relax.

Wave 08
Do nothing. Watch your Ninjas do their thing.