You have to create a Purchase Order first by going to the Purchasing Module > Select Purchase Order > Add the items > Supplier > And Save Purchase Order
When you are ready to receive the item partially simply go to back to the Purchasing Module, select Receiving, then enter the PO# in the "Lookup or Type an existing PO# to Receive" search bar:
(Note: this needs to be the system-generated id number, not a custom one if that feature is being utilized)
You will see then the results, select the PO
You have the option to pull up "Get Items" or "Get Items & Qty":
GET ITEMS will bring up the items without the quantity
GET ITEMS & QTY will bring up the original quantity you have in the Purchase Order
Enter the current quantity you are partially receiving > Add Payment if needed > Click Finish
(Note: if you are only receiving some of the items, you can delete the items you do not need to receive at this time, it won't edit the PO)
After you received items partially, when you pull up the Purchase Order again into a new Receiving, you can scan the items you have received in for that PO and you will know how many quantity is left to be received per item in the PO, or you can use the "Get Items" or "Get Items & Qty" button to automatically pull in the remaining items/quantity to be received on the PO.
This can be done as many times as needed.
Once you are ready to complete the PO (meaning everything has been received), check the Mark Complete checkbox to remove the PO from the list of suspended PO's after completing the receiving.
Make sure you ONLY check this box if you are receiving the PO in it's ENTIRETY.