Steam purchase question

Hello gentlemen,

Please, excuse me if it's not the right thread to ask questions.

So, not so long ago I came across Wolfpack project.

Is this something that's gonna be available to by from a shop once it comes out or rather be as a steam kind of game that you download upon purchase?

Having seen Subsim mod section for it I am keen on assuming it will be more like a game that you buy in store as on most steam games you can't install any mods...