From my AADSAS FAQs thread (I think it all still works basically the same way):
BASIC INSTRUCTIONS
1. Sign up for Interfolio, choosing whatever plan you want.
2. In your Dossier, "Request Recommendation."
3. Fill in required stuff.
4. Check YES that the letter must be signed and YES that it is confidential.
5. Request via email (unless, for some reason or another, you want to hand the request to your recommender).
6. If you already have uploaded your PS or resumé , you can theoretically pick them as a "supporting document" to send to your evaluator.
8. Upload your LOE matching forms to Interfolio (get them from your AADSAS account). You can fill them out yourself, as they don't require a signature.
These next instructions are taken directly from Interfolio.
You can use your Interfolio Dossier to deliver letters of recommendation to your ADEA AADSAS application. To expedite AADSAS's processing of your delivery, you should include the matching AADSAS Letter of Evaluation form for each letter you send. Here are the steps you need to complete an electronic delivery to AADSAS:
1. Log in to your AADSAS application and indicate that you will send your documents by paper delivery. This is important because of the way AADSAS processes documents sent from Interfolio's electronic delivery process.
2. Next, log into your Interfolio account. Go to your Account Settings to add your AADSAS ID to your account. For help adding your AADSAS ID, check out Adding IDs to Your Account.
3. Start a new delivery, and type AADSAS in the search box.
4. Add each document and it's corresponding Letter of Evaluation form (downloaded off the ADEA AADSAS application) that you would like to send.
5. Check out your delivery. It takes 7 to 10 business days for AADSAS to process your documents into your AADSAS application.
Note: AADSAS accepts no more than four letters through its centralized letters service. If you send AADSAS more than four letters, the extra letters will be discarded.
MORE DETAILED INSTRUCTIONS ON UPLOADING MATCHING FORMS AND SCHEDULING A DELIVERY
1. Print out matching from AADSAS.
2. Fill it out for each evaluator.
3. Scan into computer.
4. Log into your account.
5. Go to "manage dossier."
6. Click the "+Add" button in the upper left corner.
7. Upload your matching forms.
8. The forms should now be in your dossier.
9. Click the "new delivery" button in the upper left corner.
10. Put in "AADSAS" as the delivery location and select it.
11. Add all necessary document to the delivery.
12. On the next page, if you haven't already, click the blue link that says, "I'd like to associate an ID number with this application." You can then add your AADSAS ID# to your delivery, which should makes things easier for AADSAS to link them to your file (although it should already be easy).
