How do you save on Ninja Kiwi games

Usually, games will save automatically or there will be slots on a game where you can save your progress. The fact that the game is on Ninja Kiwi does not actually affect this. The problem you may be having is that you are not playing with a logged in gamer account on Ninja Kiwi, instead you are playing as a guest. Simply make an account, and play. This usually solves the problem.