MuseScore shows only 2 voices in toolbar

I need up to 4 voices on a staff and the documentation says I can do so. It even shows a toolbar ribbon with 4 voices selectable, but I only have 2 on my ribbon (see attached JPEG). Following the instructions, I am able to add the 2 voices, no problem. But I can't see how to get to voices 3 and 4. Do I need to pay for that feature, or?

I am new to MuseScore. I really like it. I just need a small boost to help me figure out the finer points that seem to diverge from the manual and the YouTube videos.

Thanks,
Steve