Models from the Warehouse often have many lines, how can I turn them off in my model?
Show us a screenshot of what you are seeing. I can think of a couple of different reasons you are seeing lines and the fix for each will be different.
Open the component to raw geometry, select all of the geometry, right click on it, choose Soften/Smooth edges. In the Soften Edges panel you may need to tick the box for Coplanar edges.
Better might be to run an extension like CleanUp3 and merge coplanar faces.
FYI I changed the topic/title for this post since it is generic to downloading 3D models from the Warehouse and not related specifically to the Campus lesson you mentioned. Hope @DaveR 's suggestions helped!
Thanks a lot!