Hi there,
I am taking the Essentials Tutorial and the same thing happened to be. As the site administrator says above, there must be a setting wrong in the tutorial. Yeah, my column grid sprouted right up to 6 floor levels, too! And I thought the same things: that I had done something wrong. I don't think so. For your info, I also ran into some glitch on the Massaro house tutorial, somewhere about step 5+/-, having to do with using a "Mesh" setting. It doesn't do anything. I restarted and tried it again 2 more times, carefully following the instructions, so there must be a flaw in the tutorial, unless I am missing something.
These walls to progress in these tutorials can be daunting and frustrating. i gave up after that Massaro glitch, but came back several days later, and dug right into the MicroSoft building tutorial. It seems each tutorial has some kind of bug here and there. And not all of the commands work in exactly the way the tutorials say. For instance, in the MicroSoft office build, when you Drag/move the column grid, you do Not want to "click anywhere" then start dragging the grid. Why: it is impossible to keep your drag at 90*. You have to start your drag on one of the vertical grid lines, so that ArchiCad can infer that you intend a straight movement. Yes, you can also press your Shift key, but then it seems you cannot then enter the 16 foot movement by typing.
Moral of the story: do not let these glitches keep you from continuing on, if you can. Hopefully, a wonderful 3D design ability awaits us, if we persevere and learn, right through the problems, and seek good advice. All my best, Rand the architect.