sda1 is an ESP partition, perfectly usable by Mint as-is. sda2 is the MacOS system partition. sda3 is the MacOS recovery partition. All of this is apparent in the image referred to in the OP. The simplest thing to do may be to use parted or fdisk or gdisk to remove sda2 and sda3, then boot the Mint installer and have it create the partitions you wish. Or, with same tool you use to delete, create the partitions you wish Mint to use, such as one for the Mint OS (to mount to /, something in the 10-60GB range, depending on how many apps you plan to keep installed, and whether you intend to keep a build environment installed), one for swap (e.g. 2GB), and another for user data (to mount to /home/, whatever is left over). Yet another option would be to create a duplicate of whatever you choose for the / partition, so that the next edition of Linux you wish to use can be tried out in real world conditions rather than from slower live media. This might be a beta of the next Mint release, or some other distro. You have choices!