Hi Wojon! Thanks for trying.
You'll need three players at the very minimum (this game doesn't make sense with two player), although the more players - the better.
All players need to log in with their Google accounts.
One player creates a room (open dialog with button at the bottom of the left column), when you select a room from the list of your rooms (left column), you can see "Room ID" at the top-center of the page - send it to other players - they need to paste it to join (also open dialog with button at the bottom of the left column).
Once there are three or more people in the room, "room creator" will have a button at the top of the room to start the game.