Extractor,
Before finalizing and completing your online AADSAS application, there will be a link for you to click on titled "Forms".
The forms link has several forms you need to download, print, fill out, and mail (snail mail) to AADSAS. Among these forms is a checklist which asks you if you have requested your transcripts to be sent to AADSAS, and if you have requested your letters to be sent to AADSAS. By filling out the checklist and mailing it in, AADSAS can tell that you have requested your letters and they will be expecting them.
I know it seems a bit complicated right now, but the process is actually very easy and straightforward. Don't fret about it, just do a couple of things before the application is available on June 3:
1. Download the "Transcript Matching Card" from the AADSAS web site and present it to each school you have attended.
2. Download the "Letters...Matching Card" and give it to your recommendation writers, or give one to your committee advisor so that they can send your letters to AADSAS.
3. Get a copy of your grades so you won't have any trouble filling in the coursework section on the AADSAS application. This will be the most time-consuming section -- assuming you are finished with your personal essay.
Last year AADSAS didn't want applicants to have their transcripts/letters mailed before sending in their online application. This year, however, they are asking applicants to have that information sent in prior to completing the application (if possible).
If it isn't possible, then have your letters sent as soon as is feasible, as hazelmei pointed out.
-G