How to add metadata to movie with multiple dvds inside

Hello, recently got back to watching a couple movies and I noticed that some of my movies that have multiple dvds (extras), is blank. I remember I use to have a nice trick for this issue which would be to just make a folder, add 1 of the files inside the folder, which would create the metadata, then just simply add the extras inside and it would still show the metadata while also having the extras inside. Well once I tried to do this, it remained blank. Only the files inside had the meta data, but the folder containing everything is blank. i know there’s been a couple updates so what is the new method to fix this ? I’ve added 2 pictures showing a movie “wrestling with shadows” as you can see the main folder is blank, but Inside the folder all the metadata is shown. How do I make the main folder show the metadata as well ?

My guess is the folder icon is blank because there is no image file named “folder.jpg” in that folder. I believe TMDB-sourced poster images are only displayed on the icons of indexed, playable video files, not the icons of folders.

so yes and no, before the updates I was able to have one main folder of a dvd movie with all the meta data, actors involved, star reviews, year etc. AND also have multiple files inside the folder that also had the same metadata. Now like you said I have to put a “” pic in the folder to show the artwork, however the metadata is no where, nor does it give you a option to search for metadata, just to use local. I can still use metadata for the individual files, just not the folder it’s in. I’m guessing the update either changed things or removed the ability to do so.