Geometry going in different axes

Hi there,

Brand new to SketchUp, I’ve just finished a handful of beginner’s tutorials following a provided plan that was just a single room with exterior walls only. Now that I’m onto my own projects, I began by drawing the exterior walls with rectangle tool and deleted the floor. When I try to add interior walls, the geometry is not attached to the floor but to the height of the exterior walls. I realize I can push/pull downward, but if I try to add geometry for say, cabinets…it looks like all new geometry is being drawn on different planes, sometimes attached to floor sometimes weirdly in the Z plane.

Separately, as I’ve built an interior room, I can’t seem to extrude the doorway away like I can with exterior walls.

We can spend lots of time guessing and suggesting things, but if you attach your model we can see what you have and can advise from there.

Malvern Studio Apartment.skp (437.4 KB)

You need to understand Context.
When you create a group it separates the geometry from the other geometry, this is a good thing, but you must enter the group if you want to edit it.
So in the gif you see me double clicking to open each group to edit before I draw the door on the actual face within the context of that group.
The blue bounding box shows closed groups and the dotted bounding box shows when it is open for editing.
Context

Thank you very much. I forgot that I needed to be in the wall group in order to extrude an opening.