So when I unpack the skelion.zip file the the script files have file extension rbs not rbz
consequently the files are not recognized as Ruby scripts by Sketchup. When I change the
file extension to rbz sketchup recognizes the file but is unable to install it referring
me to the installation instructions which are

Download SKELION plugin "skelion.rbz" from the Download Button and save it
In Sketchup 8 M2 (last version): Go to Window - Preferences - Extensions - Install Extension
Select "skelion.rbz" and accept to install it.
Accept license and restart SketchUp
Activate SKELION toolbar [View/Toolbars/Skelion]

So can anyone help me with the installation?