On the page that gave you your 20-digit EA code, there was a link. Upon clicking that link you would have been prompted to log into your SE account. Upon logging in it would have taken you directly to a page with 4 boxes, for you to type the 20-digit code into. After typing in the 20-digit code, you would have then gotten a page asking you to confirm your Pre-order bonuses (Mog Cap, Cait Sith Doll, and Early Access). Upon confirming that, you'd be taken to the final page, saying that your registration was complete.
FFXIV: Raxion Gunsoul - Brynhildr - 50PLD 50SMN 50SCH 50DRG
WoW: Raxion - Greymane- 90 Druid
FFXI: Nion - Asura - 99 BLU, PUP, SMN, DRG, PLD 50+ DNC, NIN, MNK, THF, WHM, SAM, WAR