Q: I have recently bought a external hard drive and I was told to down load a Fat 32 in order to work with my MAC/ Is this right and how do I find the download and how to install to make my new external drive compatible with my MAC?

Bad advice. You do not need or want FAT.

You want GUID and Mac HFS Standard Journaling.

You don't download when you write files, or when you format or erase a drive.

Creating a temporary user to isolate user-specific problems: Isolating an issue by using another user account

Identifying resource hogs and other tips: Using Activity Monitor to read System Memory and determine how much RAM is being used

Starting the computer in "safe mode": Mac OS X: What is Safe Boot, Safe Mode?

To identify potential hardware problems: Apple Hardware Test

General Mac maintenance: Tips to keep your Mac in top form

FAT is not something you download. It's a volume format. You select it in Disk Utility when formatting a drive, but only if you want the volume to be compatible with both Windows and OS X.