I finally downloaded and installed the Read it Later extension I mentioned earlier. After I downloaded, installed, and restarted Firefox, I got a box asking me to drag the 'read later' and 'reading list' buttons to my toolbar. I hit OK, and it opened a box for me, but I didn't see those buttons to drag. I ended up closing the box, and then I couldn't figure out how I got it. I finally figured it out - right-click on the toolbar, and select 'Customize' - so that was pretty easy. When I reopened it, the buttons I was looking for were there. I simply dragged them to the toolbar, and they are waiting for me to use them.
Somehow I found this page that explained it all. I'm looking through the pages I was on, and I still can't figure out how I got there. One of these days I am going to keep track of my path through the Web. It would be quite interesting. I did pay attention to the main site that this page is a part of, and I think it should be quite useful. It's called Learn Firefox, and it's a visual guide to the Firefox browser. I just jumped in, downloaded, and started using the browser, but I don't think it can hurt to go back and see if there's something I can use here. For instance, there's a page here called Rearrange the Order of Your Tabs. I wish I had read this earlier, because I was using Firefox for ages, and loving the tabs, before I realized I could rearrange my tabs.
Learn Firefox has different categories such as themes, extensions, bookmarks, news, and more. It's nicely organized and easy to read, and it just might help you learn something you didn't know about Firefox.