In that theme you need to also setup the blog sidebar.
Need to go into Admin -> Appearance -> Widgets and add stuff to the Main Sidebar. It should then appear on the right side of main blog page and individual posts unless you’ve changed something that’s causing it not to show.
I have widgets in the main sidebar and it shows in all pages except blog page. I have not changed anything.
Thanks for looking at my help request but I think I am just going to look for a different theme.