Hey thanks so much for playing! For moving magnetic objects, if you hold down "J" you can begin placing a magnet screw, and you can actually screw it in place once you have it the desired spot by releasing the "J" key. (Also a fun little extra hint, you might try seeing if you can place the screw on a wall :). Once you have these magnets placed, you can press Space to toggle their magnetic fields.
Also yeah, sorry if it wasn't conveyed super well haha. We kind of ran out of time for making in-game things to teach the player the controls, and so we just added a little help page that listed some of the controls on the main menu (though it still isn't super comprehensive haha). One of the challenges I'm finding in making games is effectively & organically teaching the player the controls and how to play the game. It's kind of hard to know what to teach them as I have been developing it and play-testing it so much, I don't know what is easy to pick and what isn't haha. I definitely want to try and get better at that for next time! Thanks for the feedback and hopefully this helps!