Using ctrl-tab (I’m sure that is what I was told) doesn’t get weight painting or any kind of menu; it just toggles back and forth between Object Mode and Pose Mode. I tried just tab and all the other tab-special key combos, and no luck. 
I ended just watching the last few lessons in this, as I could no longer follow a long (the automatic weights had done some very weird things that would require weight painting to fix – like part of the middle of each arm parented to the wrong arm). 
The normal way to change modes is just select the object and change modes in the menu bar dropdown, list of options. I only use tab for object to edit the rest always use the menu. There are times when infrequently used shortcuts just are not worth using.
I couldn’t find Weight Paint as an option in the menu (it seems I was trying to reach with the wrong thing selected, the armature instead of the actual object). Since I didn’t see any other way to get there and Grant said something about cntrl-tab or something about tab I tried that instead but must have had that wrong too since I never found it.
Oh well, I’ll go back and learn rigging and animation when I need it, since in the short term at least low poly (but smooth) furniture and props as are the main thing I need to make.
Thanks, though, now I know how to get to Weight Paint, and wasn’t sure what was wrong before.
Be sure your mouse is also on the correct panel because hotkeys depend on which panel you are working on (where the mouse is).
Also, Blender versions can have different configuration.