SketchUp is possibly the single worst application one could use to create a model with the intention to print it on a 3D printer. You should have your model in STL format or OBJ format and use a 3D modeling program that has a focus on 3D printing.

Even TinkerCAD is a better program than SketchUp and will generate exactly the type of file needed for 3D printing. It's a bit easier to use than SketchUp for basic shapes.

If you're determined to stay with SketchUp, you can find a method to generate an STL file here:

https://airwolf3d.com/3d-printing-ti...l-3d-printing/

It's especially important to test the model generated by SketchUp for manifold and any other 3D printing failures. There are online 3D model testing sites.