How do I put a drop on a page with a countdown and an alert-me form?

Open the page in the editor, add the Drop block (in the Store section of the block picker), and choose the Product. The block shows the product's first photo, its title (or the Heading you type), the Story written on the product, its edition size, its opening and closing times in the visitor's time zone, a countdown, and the action for where the drop stands: Add To Cart, Preorder, or, before it opens, an email form.

Choose a list under Alert Me List to show that form before the opening time; addresses go into that mailing list under Email Campaigns, and you send the opening announcement as an ordinary campaign. Leave it blank to show no form. Set Show Story to No to show only the price, the times, and the action. The buy button needs your Stripe connected under Payments; the alert-me form does not.