OK… these are the instructions for installing a plug in:
Download the .rbz file and save it to your download folder. To download it's best to right click on the download link and use the option "Save Link As... "if that is available. After downloading, Open SketchUp and go to SketchUp Preferences. Pick Extensions. Then Install Extensions. SketchUp default file format for extensions is .rbz. Select .rbz from your download folder. Install the Extension automatically. Once this is complete, plug-in will be available either as a menu item or a context menu item.
I open SketchUp and have right mouse clicked on everything and preferences is not an option. Where is it?