Old Mac Book doesn’t boot into anything from rEFInd?

I recently found an old laptop that I’d like to use but have no idea how to do anything with it. If I turn it on it opens up rEFInd with the only two options being:

“Boot EFI/Ubuntu/grubx64.efi from EFI” or

“Boot Fallback boot loader from EFI”

Then underneath those I can Start MOK utility at EFI\ubuntu\mmx64.efi, About rEFInd, Manage Hidden Tags, Shut Down, Reboot or Start firmware update utility at EFI\ubuntu\feupx64.efi

When selecting either of the boot options all it does is put me into a terminal titled “GNU GRUB version 2.04”. If I type exit into GNU GRUB it just brings me back to the rEFInd screen and that’s where I’m currently at. Is there anyway I can boot this laptop into an actual OS or is this GRUB terminal the only thing on it? If the latter, how do I put an OS on it with these options?