[Digikam-users] Folders, albums and collections

[Agustin Lobo]

I'm a bit confused by the relationships between the concepts
of folder, album and collection in Digikam.  For example,
if I have my pictures in folders in an external drive,
would each folder become an Album in Digikam? Would sub-folders
become sub-albums?
Are the pictures actually copied to the albums? Or do the pictures
remain in their original folders and just meta-data and thumbnails
are integrated in the db?
And what's a collection? Just a set of folders?

All this is not clear in the manual and it is important before the beginner user
decides the structure of its DB.

Thanks

Agus