I download the zip file from the ruby website and it has no rbz file for starters. In addition I can’t find any help with relation to 2015. Anyone please help!
Try reading the thread in the attached link:
This offers advice as to how to install and use the housebuilder plugin.
Be advised that there are two plugins. One may be more current than the other and only one has a toolbar associated with it. The posters think the one with the toolbar is the more desirable of the two.