"Customers should always be directed to your Squarespace site, and they need to make their purchases on Squarespace for their orders to appear in the orders panel. If they manage to place an order through Facebook, you won't be able to fulfill it in Squarespace, and it may display a message in Facebook that says Order pending acknowledgement from Squarespace. If this happens, contact Meta's support."
So you actually can't sell directly through IG. It has to go to your website in squarespace. WTF