What do you mean? I don’t think there is supposed to be a catalog in the entities file. Maybe you mean the manifest, and it should be in there, although not in the entities file.
Do you mean placement? well, you place them in a building the same way as you do furniture, and then hearthlings place them.
This is true. It takes an extra effort to get any mod working with better-storage, I suspect. I don’t quite know, all I read about it was this thread. I have yet to do a material tags pass. But I have to study what each material tag does, and how betterstorage does the catagorisation, and maybe add new categories myself (although this mod has just items which have a variant in the game, so it might work out fine.) I hope the ites work with the current stockpiles in all cases, so if this is not the case let me know.