This is actually very easy and straight forward, if you know where to look…
Firstly, you need to locate your .ctb folder on your computer that AutoCad references.
To do this, select the Tools tab, then click options at the bottom of the list.
Now under the Printer Support File Path tab, click Plot Style Table Search Path.
Is there a question you would like to ask about CTB files? Leave a comment below.
You can find a condensed, 2016 version of this post here.