iTunes on my new computer won't find music held on my external hard drive

I have a new computer running Windows 11. My music is where it always has been, on an external hard drive. I have downloaded iTunes to the new PC and have used Edit\Preferences\Advanced to tell it that the iTunes Media folder is at D:\music for IPOD\iTunes\iTunesMedia -but iTunes has failed to pick up my music and list it for playing. However, when I digitised a couple of CDs, these were located in the correct place and are now listed on iTunes and are playable . How can I get iTunes to locate all the other music. nb the 'Library' is shown as being called 'andyp's Library' which seems to have been automatically generated and I don't know if it has any relevance in this process.