SketchUp has official self-paced tutorials (very basic)
and specific to individual tools (watch also the videos)
and of course many user-contributed ones in 3D Warehouse.
There is a challenge: self-paced tutorials need to be opened as file (they contain scenes), not imported. I could not find a "open file" function in my.sketchup.com (sic!). A workaround is to download the model to desktop, then open my.sketchup, click the hamburger menu, click Trimble Connect and upload the downloaded file into a new project. I don't know SketchUp for Schools enough, but may it has (or will get) the ability for teachers to share such a prepared project/folder with all students.
It would be great if SketchUp added tutorials focussed on students (like they started with teaching material: https://blog.sketchup.com/tags/stem-tutorial ).