Having trouble creating outer shell

Hi I’m having trouble creating a model of my house plans. I have created the basic outer shape of it and want to turn it into a solid. I am just starting on sketchup and have no idea how! please help. shipping container home.skp (188.2 KB) I think that is the file not sure though

Outer Shell is used to combine multiple solid groups or components into a single solid group. You only have loose geometry so Outer Shell is not an appropriate tool to use.

To create a solid, you need to delete the edges and faces shown selected below.

Make sure the face orientation is correct with only white front faces out…

… and create a group or component.

Thank you! that helped a lot