Yes. The guide is at the bottom of the walkthrough pdf file, in the FAQ section for riddle solutions, or in the wiki at https://renryuu.miraheze.org/wiki/Riddles#Lum's_orpahanage_-_Dungeon_of_Cookie_a...
It's also possible to use a Riddle Key item to skip the entire area, if it's too frustrating.
11 days ago(+1)
My bad. I missed that image somehow during the upload. It's added to the wiki now.
The location is where the stone plates are on the other maps.