You can browse what farms and traders have listed, see their prices and the units they sell in, and find out who they are and where they are. You cannot buy through the site yet.
Payments are being set up so that your money is held by a bank until you have confirmed what arrived — not by us, and not by the seller. Until that is in place and working, we would rather take no money at all than take it without that protection.
In the meantime, listings carry the seller's name, location and contact details, and plenty of trade is agreed directly.