I followed the part in my email that said "Download and activation of your digital products / Click here to get access to your products"

This led me to a page in the NA Store with "HEAVENSWARD PRE-ORDER BONUS CODE" "Unlock Activation code" that sent me to https://preorder.na.finalfantasyxiv.com to put the codes in. There I put in the early access code, it told me that the code was valid and asked me on what platform I wanted early access. It asks you to confirm twice what it is. Then it gives you another code that you can't redeem until the email goes out.

"By redeeming this code, you will be able to download the game client for early access and receive the exclusive pre-order in-game items (Baron Circlet, Baron Earrings and Chocobo Chick Courier) via the Moogle Delivery service in-game mail system when official service begins."