You can save time by creating a PO directly from a Record.   Click on Quick Order within the Record (if you don't see that option, click on Toggle Inventory/Costing to expand your Record).  This will open a PO with the products from that Record, and you can chose vendor, prices, and quantity.   Once you're all set, go to Actions > Order.   Note, this doesn't send the order, you'll still want to go back to Actions on your PO screen and click on Send or Print.