burning a CD

I have burned many playlists on CDs, but not lately and I can't remember how. I have a MacBook Pro and am using an external CD player. I insert a burnable disk, go to Disk Utility, but it says the disk isn't supported. The disk icon on the left shows up, but when I click on it, "First Aid" "Partitions" "Erase" etc. are all grayed out. Also, under the File menu, "Run First Aid" and others are grayed out. I've tried this with several burnable CDs. What am I doing wrong? OS 10.15.7 --Tom in Texas