Start with the Help files at SketchUp.com There are also free tutorials and YouTube videos.
Correct tag usage involves leaving all edges and faces Untagged and giving tags only to groups and components.
I don’t know how to thank you more than THANK YOU SO MUCH! I’ll check the purge and the tags to understand. Have a great day: M
Steve, thank you so much also for your help. I got rid of this nasty bed!