The download will (I think) get you the set-upfile for the game, which you run on your PC/laptop to install it. (There
might be the need to register your installation online, which will provide you with a product key to copy & paste into a screen at the start of the game in order to activate it).
The licence for the game will probably only allow you to install it onto one machine but, in practice, if you copy the set-up file to another machine (and, if necessary, retain a copy of the product code), using it on a different machine shouldn't be a problem.
I'm not sure if the game can be played by two players online, although there is a reference in the manual to 'multi-player mode':
https://41e90006-62f8-4cdf-842f-12b14521888a.filesusr.com/ugd/cdab25_318546f99bac4d2da08e6c35378d6ca7.pdf
as well as in the press release:
https://www.tjebackinthegroove.com/presskit
You can probably use a PC game pad (such as one of these
https://www.pcgamer.com/uk/best-controller-for-pc-gaming ) to play the game but it might be worth an email to one of the guys mentioned at the end of the press release to check.
Alternatively, try posting your questions on this forum:
https://steamcommunity.com/app/516110/discussions/