Building a normal house for 500 coins and then a plant for 150 to produce food.
Now saving up 800 coins to build a large house and then saving another 300 coins to build the "warrior barrack" (symbol below the house icons).
With that setup you get a good start and can start building up your colony.

But what is the goal of the game?
I already got 1 small house 17 big houses, 3 miners, 11 plants, 6 warrior barracks and 2 times the big circle thing for 1200 coins, but nothing happens.

So how do you win / finish the game?

Good game. It has it's glitches, and it could do with a tutorial. It's fun once you get the handle of it.