You will need to learn a little about the dev filesystem.
When you plug in a usb drive it is given a file handle in the form of a filename in the /dev directory
Modern hard drives on linux are usually start with "sd" which is folowed by a letter representing the physical drive and a number representing the partition. For example if your system only has one drive, there is a pretty good chance that your boot partition is "sda1".A file called "sda" represents the entire drive, including he MBR and the partition table.
Usually, a usb drive will end up being the next drive after any hard drives and cd-rom's but you really kinda have to figure that one out. try "lsblk" It will probably either be sdb1 or sdc1 on most systems.
once you find it you just need to mount it. Make an empty directory. Technically you can do this anywhere but typically This is done in /media or /mnt.
then assuming you are trying to mount the first partition on the second drive, type:
mount /dev/sdb1 /media/"directory"
Before removing the drive you need to unmount it
both of these commands generally require superuser access
hope that helps