Got another (maybe dumb) question:

If I install on my parents computer (with internet), activate it and change Steam settings to offline,
and after that uninstall, will I then be able to install it on a computer without internet? Or is it required
for every install?

Thanks!

When you link the game to your steam you can re-download it whenever you like. So if you installed steam on another computer you'd just redownload it.

Okay, thank you