Also tried it and I have no idea what's happening, also the controls are super sensitive, the speed of the yellow thing is too much.
Viewing post in Keep hot jam comments
The right click permits to collect resources. To be able to harvest trees (green stuff) or stone (grey stuff), you have to be close to them and right click them.
Once you gathered enough "stone" and "wood", you can craft fire by pressing "c" and selecting the "basic fire" and clicking "craft".
Back to the game, you can click the fire icon and place a fire on a free position.
It's more a technical demo than a game. No win or loss condition.