The most curious thing to understand, and one that causes most of the confusion, is that Apple Mail doesn't call them folders, instead they've chosen the term Mailboxes. Okay, 100 ways to skin a cat. Regardless of the name here's how to create one and move your emails around.
- In Apple Mail go to the Mailbox menu and choose 'New Mailbox...'
- Mail will ask you what you want to name your Mailbox (example, Technology, Core, Science Team)
- Mail will ask you where you want to put your Mailbox. Choose 'On My Mac' if you just want it to be its own folder...er, mailbox. If you want to put folders inside of folders then choose the top folder you want the new one to live in. For example, I have an FMS folder that has other folders inside of it, like Camp and Conferences, etc.
- Now drag one of those 700 emails into its new home and pat yourself on the back...repeat 699 times.
If you want to get fancy you can create a Smart Mailbox which displays messages based on certain criteria that you select. For example, you can tell Mail to automatically put any message that has the subject LIT in that folder. I've never had a reason to use them, or be that organized, but you might and Apple thinks you might.