To turn on this option go to ApeksOPS > Settings, and in the “Supplier Payments” section, set “Supplier Payment Handling” to “Multiple Payments per PO”.

Once you have turned the above option on, you will see a “Payments” button whenever you edit a Purchase Order. Click it to add, view, and edit payments. To enter a planned payment (e.g. an invoice from the supplier), add a Payment and set its status to “Unpaid”).