It appears I’ve made a huge blunder by upgrading to Scrivener 3 while in the midst of a final edit. Things work very differently than they did Scrivener 2. However what’s done is done. My current problem it involves moving scenes around in the binder. Before I could you click and drag, but that isn’t working now. Yet, when I went into the manual, that’s exactly what it told me to do. If I wanted to put scenes in a different order, I could simply click and drag. However that doesn’t work now. So what is the procedure for re- sequencing things in the binder?
Wellll, you probably could step back more easily than you might think. When you updated your project, a backup in v2 format was created, and you could download Scrivener 2.9, register it with your v3 number if necessary, and finish off this book in a comfortable and familiar environment, if you wish.
That aside, of course click and drag is still a thing. We haven’t changed that, and in fact click and drag is way more powerful in v3 than before. More likely you’re running into a rare-ish macOS bug that can impact software in a very transient and localised fashion. It sometimes goes with a reboot or a reinstall of the software. Whatever the case, you certainly needn’t learn how to use Scrivener without click and drag. 
Meanwhile, if you’re having issues getting that problem cleared and don’t want to step back to 2x for now, I’ve always used ⌃⌘↑ and ↓ for small moves (left and right also work on the Corkboard). For larger moves, Documents ▸ Move To ▸ will get your item from one end of the binder to the other.