Welcome to Seller Community, @hotboxsushi!
It should be pretty simple to set up something like that. The first thing you'll want to do is create a location for your popup shop in your Square Dashboard. Next, click on the Online link in your Square Dashboard to go to your Square Online overview page. We don't currently have a pre-order option, so the next bit is a more of a work-around.
Create your items for the location if you have unique items, and then go to Settings > Pickup and Delivery. Enable pickup, then edit the location. Set the prep time for the location to the number of days until people can pickup their orders. Each day you'll want to edit that and reduce the prep time by one - this will make sure that each people order they will end up with the same day as the pickup day.
Community Moderator, Square
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