i´ve just downloaded the STL plugin from the Sketchup Website and was hoping to install the .rbz file via clicking on
Window-> Preferences -> Extensions
and then selecting the plugin (named sketchup-stl-2.1.7.rbz).
Sadly, I cannot find any trace of it there, neither the actual file name, nor something else that says STL.
I´ve done this kind of extension-installing before, back when I downloaded the SVG plugin and it worked just fine, so I´m fairly helpless now.
I hope someone has an idea on how to fix this Problem.