This is some funny terminology you will come across in Linux. When you attach a drive (like a USB, CD, etc.), you will have to mount it to a predefined (and existing) mount point. When you want to take it out, you unmount it. For most modern systems, mounting happens automatically and unmounting is just a press of a button away, but historically this had to be done manually, even for hard drives. O, the good old days… Fortunately for you, those good old days are over, and we live in the even better new days when modern systems behave like modern systems should behave, so you will not worry about mounting anything, unless you do have a horse, of course.
The important concept to remember is something called a “mount point”. This is where a certain device will be mounted, and it is represented like a folder in the file system. This means that if you want to access a mounted device, you will have to navigate to the folder where it is mounted. Nothing is set, like in Windows, where inserting e.g., a USB drive would automatically assign it a drive letter (for example
G:). In Linux, you are in control, and if you are skilled enough, you can change the default behaviour, in other words, you can mount your devices wherever you prefer or fancy.
It does probably already makes sense to mount drives in a flexible manner, instead of assigning it an immutable drive letter and only be able to access it that way. If it still doesn’t, just think of having an external hard drive always mounted in your
/home directory, appearing just like another folder. Would that not be convenient? In Linux this and many other things are perfectly possible and passable (and doable, and accomplishable, and achievable, and, and…)