Commercial Interiors lesson 6. Crown Mouldings - cannot create path for follow me

I’m following the Commercial Interiors course on Campus, my question relates specifically to 6. Context Modeling, Crown Mouldings. Eric says, create a copy of the floor to use as a path for the Follow Me tool to add skirting boards. I cannot for the life of me get this to work. I try to select the top of the floor but it’s lines do not follow the lines of where it meets the walls…any ideas?

Share your .skp file so we can see how you’ve set up the model.