The queue will open when the sale starts. At that moment you can be added to the queue on a first-come-first-served basis.
Once you have joined the queue, you can either wait on the queue page or you can enter your email address to receive a notification when you are able to purchase a pack.
If you choose to wait on the queue page, when your turn arrives you will automatically be redirected to the pack page to select the number of packs you want to purchase and complete the payment.