It's somewhat the same as a hard drive but no moving parts. They are both storage devises.
They come in several capacities such as 1gig, 2gig, 4gig etc.
I have always just named the folder on the computers hard drive and either dragged and dropped it to the thumb drive in Windows explorer or right click the folder and send to whatever drive letter it takes on when you plug it into the computer.
You can see that by going into my computer before you plug it in and see what's listed then again after you plug it in to see what drive letter it comes up as.
You didn't say what operating system you are using so it could be a little different.
Is a thumb drive like a portable hard drive ? I have two e-mail accounts with folders for saved e-mail for both of them. Can I create a
folder on the thumb drive and copy those folders to the thumb drive ?