Two hard drives

I have a mac operating on leopard and I have two external hard drives. How do I delegate which ones retain what type of files? IE One for media, one for word documents?

Depends, are those 2 drives the same? On either case you’ll need a software able to manage separate files if that is your intention.

What model number are the drives if they are WD?

if you’re just talking about identifying the drives, can’t you rename them?