To view your Stock Order List, under Stock, click to Stock Order List. The screen below is displayed, showing all the items which you need to reorder. Items will be added to this list when they reach their reorder quantity. 

You can also add items into this manually by choosing Add Items from the top-left. Press Scan Barcode, and either scan the label or just enter the number manually and press enter. It will then be added to this list.

Use the Filter Selection to help narrow down your results. You can tick the Order checkbox to add items to your Reorder List, and they will automatically add 1 to the Qty column. You can over-type this with your own quantity if needed. When the item has come back into stock, or if you have made a mistake, right-click on the relevant line and choose "Remove from Order List".

This page works in tandem with How Do I View Items Sold?