I installed Zotero for Firefox but I can't see it
You may have inadvertantly closed the "Add-on Bar" that runs along the bottom of your browser window. In order to fix the problem Go to the VIEW MENU, select Toolbars, and make sure that there is a check mark beside the "Add-on Bar."
I Can't Add Items to my Group Folders
Before you can add items to a group folder you must first add them to your own library. Add the item to your library and then drag and drop it to the desired group.