How can we sync the "Qty in stock" field (in CRM) with the "stock on hand" field (in Inventory)?

How can we sync the "Qty in stock" field (in CRM) with the "stock on hand" field (in Inventory)?

As the question, I have a problem when trying to sync the figure of "qty in stock" fields in Zoho CRM with the "stock on hand" (or "Available") in Zoho Inventory. I tried many different ways...

Please help!