So you're interested in Google SketchUp eh? Well why don't you sit yourself down and read the follow instructions for beginners.
Open the program: Google SketchUp
Select the first template
On the upper half of the program you have a toolbar, this has many tools for creating shapes, erasing, and drawing.
Basically I used most of those tools to help me.
Main tools used: Erase, Box, Circle, Follow Me, Scale, 3d Text.