Transferring catalog and images from external hard drive to an internal drive

You can follow these instructions:

https://www.lightroomqueen.com/move-photos-another-hard-drive-leaving-catalog/

Using Mac Finder, copy-paste the folder tree that contains your images to the desired drive.

Using Mac Finder, copy paste the folder containing your *.LrCat catalog to the desired drive. Technically you could copy just the *.LrCat catalog file, but Lightroom would need to rebuild the LrData folders you did not copy.

Note: these are COPY commands not MOVE commands.

After the files are copied, you will need to go to the Folders panel in Lightroom and "relocate" or "find missing" on the top-most folder(s) that you transfered. (All the subfolders and files will be corrected automatically from there.)