My question was about how to add more walls after a "room" has been closed off or considered complete. While drawing, it automatically adds walls until you hit escape. After that, adding a new wall to any existing wall doesn't really join it to the room properly.
A common situation would be ...

How can I add walls to an existing room? I have pressed the escape key, or closed off a room. Now I need to add additional geometry to the room. How can I insert walls into an existing room? The only way to add new walls that I have found just starts creating a brand new room.

I tried to adjust the scroll wheel settings of my mouse. It was already very low, but I adjusted it down to the lowest value, but unfortunately that didn't make any difference with the minimum distance that it pans.

I had already watched that video, and I just watched it again. It does not address my question.

Is this a bug? Or is there something that would prevent zooming with the scroll wheel? It doesn't work in any situation.

Sorry, I should have explained better. I didn't really expect there to be a choice between using the two different keys; I meant to say only that I tested using Shift just to see if maybe that would work.
When I place the mouse pointer on the plan, Ctrl + mouse scroll does not do anything for me. I ...

What do you mean it has no meaning? What even is the point then if you cannot accurately place any wall? I didn't come across any debates so far in my searching, but are you saying that it is impossible to define wall placement without just guessing?

If I have a dividing wall between my living room ...

None of my interior walls (drawn using the Create Rooms tool) show up in the 3D view. If I open the window to modify any room, it shows the height as 2 1/2" and the thickness as 3/8". Both of these fields are grayed out, so I am unable to increase the wall height.

How can I enter dimensions for interior walls? All I can find any help on is how to show existing dimensions, which is not what I want. I need to define the dimensions.

I have tried using the Edit Points plugin to adjust the (x,y) coordinates of each endpoint. But the dimensions are given as ...

How can I zoom in the 2Dj view using the mouse scroll wheel? I can't find this in the help anywhere. I read a couple of places that holding Ctrl or Shift should work, but it doesn't. Scrolling with just the scroll wheel alone also does not zoom. The only way I can zoom in the 2D view is using the ...