Link purchase Order number with items purchased

Hi guys,

I am new to Jet and am hoping to get some help.

I am currently writting a report showing purchase order number and want to link this with the list of items purchased on this purchase order number.
To look like this:

PO Number Item No.
106344 123-43
124-54

I am using ROWS; PURCHASE HEADER table as the source.
What table do i use to pull in the items and how do i link it with the purchase order nnumber?

Thanks