Can you add a ceiling to a completed 3D Model

Hi everyone, I am really new to SketchUp and have drawn a 3D Model without a ceiling. Figured I could add it later but maybe not? If anyone knows how to do this I would be grateful for any advice. Please keep it simple, as I said I am only learning to use the program at the moment. Thank in advance!

Just as an idea
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But it’s best to start learning the basics of SketchUp from here:
https://learn.sketchup.com/track/sketchup-fundamentals-part-1

Learn about groups, components and tags.

Thank you, I have seen this tutorial but not until after I have drawn everything else. Is there no way to add a ceiling after the rest has already been done? I don’t want to have to start again. Thanks for your reply!

It is not enough to see a tutorial, you have to understand the logic of what is presented in it, and then it will be easy for you to choose the technique and the way you work something.

In this case, creating groups for each element: exterior walls and floors.
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To make your work even easier, you assign a certain layer/tag to each created object, with which you can then control its visibility.

Ok, thanks anyway.

Editing an object (ceiling)

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When you created your house model, did you group each element of it (walls, floors, doors, windows, etc.)? Did you assign them layers/tags?