Napoleon total war pc game.?

hello i just received my copy of the game in the post today it's brand new but it says i have to download it to steam or what ever, anyway i was wondering if i downloaded it on my laptop would i be able to download it on my gaming pc which will be built and finished in a few months? i heard somewhere you can only play it on one system such as if you play it on a laptop you can only play it on that laptop you downloaded it to. please help i want to get playing :( thanks