Hi there, How do I make a field which calculates the total number of items in a sales order. For example, I sell handbags to retailers, and sometimes they will order a total of (for example) 87 bags, in 30 different different styles (for example, 3 of these, 2 of these, 5 of these in black etc etc)

I want to create a field that shows the total item count for this order, and also, when I export to a PDF using inventory template, how do I put this on my Sales Order Confirmation PDF template? 

At the moment I have to manually count each item to check that I have not forgotten to enter an item. I just want to confirm that if it's an 87 bag order, I have properly entered 87 pieces.