To send an entire folder, you'll need to create a .zip file. In other words, compress the folder you want to upload. That will both keep the original structure intact, as well as the name you gave the folder.
Not sure how to do this? Just right-click the folder and choose "compress..." if you're on a Mac.
If you're working on a Windows machine, here's what Bill says:
Locate the file or folder that you want to zip.
Press and hold (or right-click) the file or folder, select (or point to) Send to, and then select Compressed (zipped) folder. A new zipped folder with the same name is created in the same location.