Use a standardized way of numbering Purchase Orders.
Leave Enter P.O. # Manually unchecked and let DesignerLogic number them for you- it will start with 1 and go up sequentially from there.
Check Enter P.O. # Manually and use your own numbering system. For example, Project 'Smith House' might use SMTH001 for the first Purchase Order number.
Supplier Address is the billing address for the Supplier. Do not leave this blank because it is what shows up on the Purchase Order Printout.
Terms and Conditions are the legal language at the bottom of the Purchase Order. When you first create it the 'Terms & Conditions' from Account/Settings will be pasted in to the new Purchase Order. Use Edit to adjust the Terms & Conditions for just this particular Purchase Order, if desired.
When you are finished filling out the Purchase Order form and click Submit the Purchase Order itself OR the Items List will open (depending on which page you came from). There you can add new or select Items to put on the Purchase Order you just created.