Makes sense (this is Steelman but I have changed email address and alias)
If that is the scenario, I would suggest two alternative ways of doing it:
1) A gallery of items with a text input control for each item. The number that the user enters into the text input is the order quantity for that particular item. Then there is a button outside the gallery "Submit order" that when pressed send the order at once with this sort of pseudo code:
ForAll( GalleryItems, If ( Value(TextInpt.Text)>0, Patch (MySharePointList, MyRecord, {Order quantity: Value(TextInput.Text)})))
2) An order form, with a button for "Add to cart". The button, when pressed, adds the order to a local collection "ShoppingCart" via a Collect statement. Then you need a gallery that displays the contents of ShoppingCart, with a button "Submit order" that has a similar pseudo code as in 1 above except that it starts with ForAll ( ShoppingCart etc. etc.
Please let me know if anything is unclear or if you need more details on how to proceed.