How does the waitlist work?

After your shopper comments for an item that's sold out, they'll get this message if this is the first time they've been added to a waitlist:
If they've already been added to a waitlist before and clicked "Get messages" in the past, they will just get automatically added to the waitlist and get the following message:

And once the product becomes available for them to buy, they'll get a message with their invoice:

The "Buy Now" button goes to a draft order that has the note that this was a "Soldlive invoice (from waitlist)"

The first customer(s) that got the back-in-stock message has a certain time to make the purchase. This time is determined by your back-in-stock hold time which you can customize in your Waitlist tab:

Once that hold time expires, the next person who was on the waitlist for that item gets messaged

Some additional details

1) You'll want to keep the defaults: "Track quantity" checked and "Continue selling when out of stock" unchecked:

2) If the shopper who got the back-in-stock message clicks "No Thanks", they can no longer click on the Checkout button and the next person on the waitlist gets a back-in-stock message
3) If you see a ! next to the "Waitlisted" status in the DASHBOARD table, that means the commenter did not click on the "Get messages" button and is NOT on the waitlist for that product:
4) When they click "Get messages", this also has the benefit of subscribing the shopper to get messaged whenever you go live. 
5) Waitlists on Instagram work the same way
6) We automatically take into account the # of people on the waitlist versus the quantity of inventory. For example, if 10 people are on the waitlist and you updated your inventory from 0 to 5. Then the first 5 people on the waitlist get messaged. And if they click "No Thanks" or their back-in-stock hold time expires, then the remaining 5 people will get messaged in order.