Creating new catalog from backup

Hi

I've upgraded my Mac to a new version with the M1 processor. I've backed up the catalog from my previous Mac to import as the new catalog. My question is - the backup has created copies of jpg and raw files which I hadn't anticipated however I want the catalog to link to the original location of the files. Have I done something wrong in the steps to create the backup? And/or can I delete these unwanted files when I create the new catalog from the backup on my new Mac?