New SketchUp users and it seems from the YouTube video on how to use Sketchup to design a Small House, that the best plugin to use would be House Buider. This program is too hard to install! It looks like you have to be a computer enthusiast to set up any option.
It looks like you have to be a fortune-teller to help you…
Generally it should not be difficult to install extensions. If you encounter challenges, then it is a very specific case. Did the video give you instructions from where to obtain it, or do you maybe have a wrong version or wrong instructions? Can you tell which extension you mean (= link to identify it) or which video recommended it (link)?
This is an old plugin.
There are several newer, and therefore, better extensions available.
Do some googling…
However, to help those less demanding users [who need the simple older version], through the morass of old files and versions, I made the definitive pair of RBZ files for the last/latest iterations of the files for both unit-systems - and they are available from SketchUcation:
Use the metric or imperial version links to access the download links.
Use the native installer on the RBZ you get.
You need to be a SketchUcation member to download files, but their register page has links off to a simple free membership option…