This question is primarily aimed at people who were already able to purchase the Steam Deck they placed a reservation for, or just anyone who has seen or knows the exact process.
As far as I understand, Valve sends emails to everyone who reserved a Steam Deck, in the order that those reservations were made, in weekly batches, the first of which was sent yesterday at the time of writing. Those emails are said to contain a link where you have 72 hours to make the actual purchase.
Is that email the only way to actually purchase the Steam Deck, or can you also tell that it's your turn and proceed with the purchase inside Steam itself? Specifically, I'm talking about the official store page, which (for me) currently displays the date the reservation was made, the expected quarter of the year it will be available to order, and a "Cancel Reservation" button. Will that button be replaced by the option to purchase when it becomes possible, or do you just have to pay close attention to your emails?