1. Go to the uBlock Origin Releases page at GitHub (a version-control repository and Internet hosting site).https://github.com/gorhill/uBlock/releases
2. Scroll down until you see the label "Latest Release" in green letters. It should look something like this:
a. Look the right, under Downloads, and you will see links that look like uBlock0.<something>.xpi .
b. Look for the one with firefox in the name (oh, the irony). This is the XUL edition that will properly function in Pale Moon.
c. Click on this link. Click "Allow" if prompted by a pop-up.
4. Now look in your Add-ons Manager. You should see uBlock Origin installed with the beloved Blue Dot.