You can let Mint format the drive automatically, by selecting "Use whole disk" in the installer, and then choosing the right disk.
In case there is another operating system on the disk (such as Windows), you can leave unallocated space on the disk and then choose "Install alongside Windows (or other operating system)". That will automatically create all necessary partitions in the unallocated space of your disk.
And indeed, / (the root) is the only partition that you definitely need. Swap can be good for hibernation, it needs to be just a bit larger than 6GB (the automatic formatting in the installer will do this right). Other partitions are optional. Some Linux distros (like Fedora) create a 500MB /boot by default, but you do not need that partition.
Registered Linux User #528502
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