I learned how to add tabs to a group but opening the groups was confusing to me. I found no way to open groups in their own windows. It uses hidden tabs in which you switch between your group and your normal casual browsing and it is not intuitive. Adding tabs to a group was awkward because you can't select your tabs among the already opened; I had the close the tabs I did not want grouped. Simple Tab Groups comes with many features that were not much useful and the core function of it is much to be desired. There is no reason to use this because you can just create a folder and store your tabs in there to simultaneously open all those tabs later from your bookmarks.