Attached is a view of a collection which has many subfolders that I created by Right clicking and then giving a name.
No, that's a collection set which has further collections in it, not folders.
If you right click in a collection set you'll have the option to create another collection within a chosen set. You can't create a sub collection in just a simple collection, the top level needs to be a collection set.
It's important to understand that creating a folder within the folders panel creates an actual folder on the hard drive that any other programs can view and manipulate.
A collection is just a organisational element with Lightroom's catalogue structure that is only seen within Lightroom. It's an important difference and folder and collection sets have different icons to represent them.