If you'd like to convert FLAC files to Apple Lossless, you can have a try of Apple Music Converter, which can meet your needs with three steps.
Just add FLAC files to this program, and choose Apple Lossless format and then click the 'Convert' button, all steps are done. Just wait for your Apple Lossless files.
Just add FLAC files to this program, and choose Apple Lossless format and then click the 'Convert' button, all steps are done. Just wait for your Apple Lossless files.