Oh yeah i'm really sorry, i forgot to put something to indicate the collection zone, it's on the side of the big ship then you can get money.
Now that I understood where you need to put the debris, I managed to actually play the game! It's much better than I initially thought. The progress felt satisfying and the enormous range was pretty cool. The movement was a bit wacky but I guess that was also fun. I got all ships fully upgraded and had 16000$ left :D