Use df, lsblk or sudo fdisk -l to list the available drives on your system.
Tip: use dmesg to see what drive was most recently plugged or unplugged,
or, run ls /dev/sd* before and after plugging in a drive.
Make a directory under /mnt. This will be your mount point. For instance:
mkdir /mnt/sandisk
Mount the drive with sudo mount /dev/<drive-name> /mnt/<mount-point>. For instance:
sudo mount /dev/sdc2 /mnt/sandisk
Unmount with sudo umount /mnt/<mount-point>.