Thanks Gidon Yuval and Wo3Dan for your quick responses!

I tried all the techniques and they removed my frustration significantly.
The tutorial attachment is very helpful. What a stylish 3D model too.

Hello,

I recently started using SketchUp and it is one smart program.
However, I'm having difficulty managing my horizontal/ground plane.
For instance, when I have a person I'd like to place on a second floor
of a building, I cannot position it properly ON the floor. I thought I did,
but when I look at it in elevation the person is floating above the floor.

Similarly, when I accidentally dragged a component below the ground plane
(be on dotted blue axis), how do I bring it back to the ground other than
move-snapping its corner to the blue-green-red axes intersection?

How do I anchor objects onto a given surface (ground, floor, table, etc.)?
Hopefully my explanation was cohesive.

Thank you.