Pegasusearl while you’re on gnome shell extension site look over at the right side and check to see if the “Compatible with” drop down menu is set to “Current version”. I have experienced issues with some of the extensions when it has been set to “All versions” as they do not always work with the various versions of Gnome (i.e. versions 3.18, 3.20, etc…)
Also check via Tweak Tool if a particular extension has settings that need to be adjusted. Let me know after checking if you’re still having difficulties.