To make a new ObjectType you would need to use XPOR System Modeller.
Under the "Home" Ribbon you wll see a button called "Add Object Type", once clicked a form will open for you to fill out your new ObjectType's details. For your Watch object you would want to inherit Product so that it will work with the Ecommerce system.
If needed it is possible to add new Properties to the ObjectType, for example a constant set for the watch type (Analog, Digital, Diving, Dress, Mechanical etc)?
When you are ready you can apply your changes and build the new ObjectType.
Now you can add the interface to the ObjectType so you can set the properties of the watch and you are ready to go sell watches.
