You can share your game to the Content Library. When start your game by pressing the play button, a pop up will appear and suggest sharing your game to other users.
If you don't want to share your game at that time, you can always do it later by pressing the share button on the bottom right of your screen.
It's recommendable to set up a description for your game. You can also add other information like keywords and categories. This makes finding your game easier for other users.
The changes that you make to your game after sharing it don't automatically sync to Content Library. So after you've shared your game and later decide to make some changes to it, you have to sync your game again by clicking the "Sync game now" button.
If at some point you don't want others to see your game, you can delete it from the Content Library by setting the "Delete game" toggler on and syncing the game.