iTunes library on new PC

I keep my music library (i.e. the actual files, folders, etc.) on a NAS drive. Having purchased a new PC and installed iTunes, I need to know how to get my "new" iTunes to see the NAS library (i.e. list all the albums and tracks).

My file structure is like:

NAS Drive

My music

iTunes music [then subfolders by artist & album of everything I bought from iTunes or converted from vinyl to MP3]

Amazon music [then subfolders by artist & album of MP3s I bought from Amazon]

I think I always had "keep media folder organised" selected from day 1 of using iTunes (with iPod!) many moons ago, hence the subfolder structure of artist, then albums, then numbered tracks.

Is it simply a matter of telling my new iTunes (in Edit, Preferences, Advanced, iTunes Media folder location) that the location is "My Music" and it will build the new library list of everything in all subfolders beneath that?

Or do I need to add each and every album folder individually (in File, Add folder to Library ...)? I hope not, that will take forever!

Or is there an index file somewhere (either on the NAS or on my old PC with old iTunes on it) that I need to move across to my new PC and tell my new iTunes about?

TIA for any help.

And apologies for using swear-words like "PC" and "Amazon"! :-)