From the dashboard left hand menu, navigate and click on the 'Product Stocks'
This will open up the dashboard with all products of simple type that have inventory stocks associated.
Use the filter tabs at the top of the dashboard to help identify one or more products in which to manipulate the stocks value.
The 'Stock Qty' will show the stock inventory value at that time, with 'Update Qty' allowing you to scroll down the product list and update manually the inventory without ever going into the product detail pages to update individually.