Partition and Format the External Hard Drive for FAT32

First check if your drive needs to be formatted by checking the current Format\File-System of the drive.
Open "My Computer", right-click the external hard drive you want to use, then select "properties".
Make note of the Drive Letter of the external hard drive as this will be important later.
If the "File-System" is already FAT32, you can skip this step.

If you have anything saved on the hard drive, you should back it up now as all the data will be lost once you format it.