How to add Movie Collections

[Host-in-the-Shell]

Could you clarify what exactly are you having trouble doing? Far as I know it's the same procedure: by clicking the three dot menu on the media you want to create a collection and adding them individually, or if you can search for all the items, you can hold left click on the first item and then it allows you to select in bulk and add them all into an existing collection or to create a new one with the selected content.