To set up an online user group, you must be the owner of an active online group add-on. The add-on has a term of one year. By purchasing the add-on again, you can extend the term by one year at a time. If you want to purchase an add-on, you can proceed as follows:
Press this button on the app bar of the game view to show the list of secondary commands. On a PC, you can use the menu of the title bar alternatively. This menu is more detailed than that of the app bar, so you can reach almost all the panes directly.