Presales are automatically delivered on the "Street Date."
After purchasing a presale item you will receive an email letting you know the date when your download will be available. Upon the release date of the item, you will receive a NEW email with your download link.
Note: The original email you received when you pre-purchased the item will not updated to include the download link for the full release. You will receive a different email at the time, containing the download link for the full release.
If tracks from your purchase have a release date prior to the album as a whole (i.e. prerelease tracks/instant gratification tracks), those will be delivered on their respective release dates.
Note: Some Gmail users have reported finding their downloads in the “Promotions” folder.