How do I add a second floor?

Hi I am very very new to Sketchup.

I was trying to learn the basics and build a second floor. A very simple building that is basically just a block.

What I did was I first constructed the building on a new surface with OpenStudio and then got the first floor.

But when I was trying to make the second floor by adding a new surface, an error appeared saying how a surface can only be on the roof or top of a building. I am literally on the roof and I do not get why this is happening.

Then I opened a new document and to my surprise, this was fixed somehow (I still wish to know why that error message occurred) and I was able to add my second surface. Then, when I copied the first floor over and tried to drag it to match the vertices of the bottom level, they do not align automatically. You guys know how for AutoCAD or even stuff like google slides help you align textboxes by their edges, yeah, Sketchup just does not seem to do that for this one.

Please please please help if you guys can. Any advice is welcomed!

Thank you all so much in advance.

When I am aligning one component on top of another, I use a combination of guides and rotate tools. It takes a little practice, and it helps to type in the amount of rotation when you get close (even by 2 degrees or less). To set the rotation tool on the correct axis, use the Page Up, Down, Left and Right arrow keys.

Can you post your skp file here so that someone can have a better idea on how to help you.

Use the little arrow pointing up from a block (eight icon from the left). You will see a popup message stating “Upload” when you place your cursor on top of it.