After partitions are created and you've installed Mint (or additional Linux distro's), create a mount point for the data partition:
sudo mkdir /mnt/DATA
Mount the partition:
sudo mount /dev/sda5 /mnt/DATA
Take ownership of the mount point:
sudo chown -R yourusername: /mnt/DATA
supaya ter mount otomatis.. edit fstab
supaya ter mount otomatis.. edit fstab