Buy the game.

Thank you)
I was suggested to download uPlay here, is it the right one?

uPlay is a program that launches the game (a launcher). It will install automatically when you install the game.

You will be able to play with those who don't have all the expansions; the only requirement is that the game is updated to version 2.1. Also, owners of the "Buka" version cannot play with those who have purchased a different version of the game. The Steam version is more expensive, but it provides a wider selection of opponents.