Cannot Accept Waiting Room Challenge

When I go into the waiting room, get an option to "register" for a game but I have no options, links, buttons, or anything else for accepting any existing challenges. Is this a bug, or does one perhaps need to be a paid member to use the waiting room in that way, or... what's going on here?

It looks like I will have to post a challenge and wait for someone else to accept it. The game's documentation makes it seem like I should be able to accept a challenge that's already on the board, though.

No, that is not how it works.  Registering at the waiting room simply adds your name to the pool of others who have registered.  At various intervals, the computer will pair you (unpredictably) in a game with another registrant, provided that neither one of you have used any features to exclude players (such as max/min rating).  If you are registered, and if other appropriate players are registered, the system will start your game; eventually.  Paid membership gets you no advantages, except an asterisk by your name, more vacation days, and the right to start user tournaments.

(meow)

Yes, what MisterCat said.

You can also sign in other types of tournaments (user tournaments, infinity, monthly cups or the championship). The types of tournament has differences, regarding when you should expect for the games to start, regarding expected number of games, etc.

The fastest to start is usually the monthly cups.

You can also invite anyone, for unrated games.

Ok, thanks for the info.   :)