The tutorial says I must use key [A], and it does nothing.

Did today's patch fix it?

That is gamepad A not keyboard, A does nothing on the keyboard. Unlike most games it doesn't detect if you are actually using the gamepad and gives you gamepad keys if it is attached at all. If you don't have one attached it looks like it just tells you to click stuff rather than giving you the keys. You can look at (but not change) the keyboard keys in the settings menu by clicking the keyboard image at the upper right. There isn't a key for looking at other players, you need to click the icons for that. The main keys are Space select, C confirm, X back, D and S for other habitats.

reinstalled and uninstalled again: game still telling key A and it does nothing