To create a new product manually, navigate to the My Products tab under the Products menu. Click on the "Create New Product" button located on the right to open up the product interface.
Along the top of the interface you will see a number of tabs; Content, Distribution and Reviews (if subscribed to feature).
The content tab is where you input all of your product information. You will see a menu on the left with the different content sections you need to fill out. Go through each section and fill out the fields that are relevant to your product. If you need help, you can hover over the field name to display a tooltip detailing what information is required in that field.
You may have fields that are consistent across all product, if this is the case you can use the Multi Product Update feature of Magpie to speed up the process of completing your product content.
The distribution tab of the product interface is where you can set the visibility of the product. If you do not want the product to show on Magpie front end, uncheck the Display on Magpie Directory box.