To edit group details start by clicking the group section on your home screen.
Once you have chosen the group section please choose a group you own then open up the groups page as shown below.
Once open click on the picture of a pen or the Edit button if on IOS, both of which will be in the top right., you will then be directed to the groups edit page where you can-
Change the language of your group, Make your room visible to the public, Give your room a category where it can be found in discover groups, give your room a password if you are premium, Make your room let only certain leveled users enter and change your admin settings. please fill in the sections you wish to alter tick the agree box and save.
You can also add a password from this page if you have premium.
Have fun with your now customised group!