I think there's a bit of a misunderstanding here, plus I was writing a comment in the translator and immediately pasted it without seeing how it specifically translated my thoughts:
I thought so - went into the game and saw that the whole basis is explained in the levels themselves - so did not go into the description.
I was specifically talking about the moment when you have to use ‘space’ to change the selected beam.
I didn't realise that I had to do it in the mode while I was controlling the beam (plus that after the spacebar I had to click the arrows). That's basically what I'm talking about