@rutpin
So you installed the FredoScale extension.
I assume you installed it from an RBZ you've downloaded, using the Extension Manager > Install method...
When it's installed it doesn't appear in the 'normal menu list' - by which is must assume you mean 'Extensions', it's under the 'Tools' menu, and also has a Toolbar which you could activate.
I don't understand your 'where do you open the icons' ?? Please explain...
You will also need LibFredo6 [for the helper methods] and the SketchUcation Tools [for the licensing] installing...
Restart SketchUp after the installations to sync everything.
After that it doesn't appear, or it is not at least listed in the Extension Manager dialog, then come back for more help...