Okay.... Read all the threads in the forum on this subject.
Wasn't able to use the if/else commands version per the instructions because I have sidebars designated as Left and Right, rather than the generic empty sidebar function in page.php.
So, finally found the easy instructions for creating a Template file, and WordPress automatically created the Template dropdown.
Created a new Template file, omitting the Right Sidebar, and of course in the Forum page selected that Template.
Problem is, the Right Sidebar is STILL SHOWING...???
I looked at another thread, and it said to check if other files were calling it (such as loop.php), and I couldn't find any, and I cleared caches.
How can I get this to work?
Here's the code in my new Template file: