How do we update OnHand and OnOrder values when linked to Shopify

The process is as follows

1. generate a po in stocktrim, and send off to your supplier via email

2. once you receive this in stocktrim, the onhand and onorder amounts will update

3. our updated on hand amount will sync back and update shopify

4. then shopify will return to StockTrim the current onhand value at the next sync