Is it possible the Next (and Previous) buttons don't show up in your pop-up window because you have changed your windows display DPI (dots per inch) setting to a higher value? Something to look into, anyway.
Somebody else here on this forum had a similar problem. See the "Dialog boxes don't display fully" thread about 20-25 threads below...
After I posted the question I remembered from an earlier version that an action is required. I'll check as soon as I can. I usually don't use the Tutorials anyway. Thanks.