Inventory Planner provides the ability to push received inventory quantities to your eCommerce platform (BigCommerce or Shopify).
In your Purchase Order, enter amounts of inventory received.
Then click 'Save'.
You will see the amounts received and the date they were received. Click 'Update quantities in BigCommerce' (or Shopify).
A box will appear showing both your current stock and what the stock will update to in your store. You can still modify amounts at this point. To push inventory to your store, click 'Update selected products'.