www.algodoo.com

So i wanted to recreate GD (Geometry dash) but i dont know how to make an object move forever.
Also i saw it on the algobox.

You shouldnt post question like this in the Tutorials subforum. Insted, use the thyme subforum or the Help/FAQ Subforum.

Regarding your question, you need to use the integrated programming language "Thyme" in order to manipulate the object to move and behave as you please. In your case, you should put this in PostStep:

(e)=>{
vel = [10,Vel(1)];
}

Replace 10 with any number to change the speed.

If you have more questions regarding the usage of thyme, feel free to send a DM to me on the forum!