As far as I remember since the instruction aren't available in lodestone due to maintenance, all we console players had to do was to purchase the preorder and download that initial file when it came up and we're set to go:

PlayStation®3 / PlayStation®4 download version (FINAL FANTASY® XIV: Heavensward™ - Early Purchase) Promotion code registration is not necessary. Early access and the bonus items will be automatically linked to your Sony Entertainment Network account at the time you buy “FINAL FANTASY® XIV: Heavensward™ - Early Purchase” (available from Friday, 19 June 2015).