To access the 'Create' and 'Explore' sections of 'The Universal..' you need to join the Old Man Game Development Membership Scheme ; an exclusive club that contains only the Best People around.
As well as freedom to explore the player-created worlds of TU, members also get other Old Man games for free, plus exclusive access to new features and content.
Membership is currently invite only. That may change later, and the more people who sign up for membership, the more games will get made. And vice versa, hopefully.