1. Go to Settings > Item numbers > Stock items

2. The list of stock will be displayed here. You can add new items by clicking 'Add Item'
(All fields with a red * are mandatory)

3.  To edit current stock find the item in the list > Click the pencil next to that item to edit

4. Edit the details in the pop up box

5. Click 'Update'

When you invoice a stock item the 'QTY On Hand' will be updated in the Stock Items.