What am I doing wrong? My walls won't raise up?

I have been teaching myself SketchUp and using the Pro version on a trial basis. I only have 2 days left before I go ahead and pay for it or completely throw in the towel. I’m trying to take a 2D imported image of a floorplan and make a 3D rendering. But I get stopped every time when I try to raise my walls. I’ve watched every tutorial at least 3-4 times, tried different methods and still keep doing something (or multiple things) wrong. I used the rectangle tool and the line tool to draw my interior walls and I felt like I finally got every single corner and line drawn perfectly but I can’t pull up the walls! (Granted, this was the first time I used the offset tool to do the exterior walls.) I’ve read the other posts from folks having the same problem and learned from those mistakes, but I’m still not doing it correctly. I think it has something to do with the fact that I grouped the exterior walls and floor. I would really, really appreciate some assistance. Thank you in advance!
Exterior Walls and Floor - Something Wrong.skp (3.2 MB)

You walls aren’t (all) in the groups you’ve made.

And these lines (edges) are a little strange.

But by getting into the context of the Group (double clicking) and selecting the face, and using Push Pull, the outside walls lift like a charm.

Normally you could Cut the rest of the geometry (the interior walls) and then go into the Group context where the outside walls are and Paste in Place to put this back together. But in your case you did manage to Push Pull some of the interior so it isn’t flat anymore.

The darker lines give a clue to where problems may be found.

Here it is when the line is connected.

Presto.

Thank you so much!! I really appreciate you taking the time to go through this with me. As I was waiting for a reply, I redid all my interior walls and zoomed in to a micro level to make sure I connected all my lines. AGAIN, I got to a point where I see dark lines in the middle of the floorplan and when I try to select just the walls, I get the middle of the rooms selected as well. How do I find where the issue is? Just zoom in on every single line/point to find the issue?
Interior Walls Build BUT…skp (3.2 MB)

Some times you just need to use intersect faces with to fix it.
GIF 21-01-2024 3-14-58 PM

The technique Box showed looks like it will solve your issue.

There’s a little catch that snags a lot of people that may have gotten you. Uncheck, “Enable length snapping”, in Window → Model Info → Units. Save a template with it turned off.

Screenshot 2024-01-21 012851

I have a sneaking suspicion that may have been the part of the problem previously.

Screenshot 2024-01-21 011718

To help achieve your goals, some time spent at the SketchUp Campus and at the SketchUp - YouTube channel will be very worthwhile. Both sites are from the SketchUp team. On the YouTube channel, pay attention to the Square One Series and Level UP series. They cover the basics for each tool.