LayOut is the tool for creating documentation from your SketchUp model. You start in SketchUp, draw your project and create scenes to show the different views. then you can send the file to LayOut, add dimensions, labels, other text, perhaps photos or whatever. then export a PDF file to send to a client or use it to do a presentation on screen.
There’s a dynamic link maintained from the SketchUp model to the LayOut document so it you edit the SketchUp model, those changes can be shown in the LayOut doc.
What are you planning to use SketchUp for? What sort of projects will you model with it/