Go to 'Settings' --> 'Solutions'
Open the RAMCOSubscriber Solution
Expand the entities and go to 'Product' --> 'Fields'
Note: If this entity does not exist, please click 'Add Existing' --> 'Entity'
Add the product entity:
Go the the 'Fields' tab and add the 'Product Type Code' field:
Expand the entities and go to 'Product' --> 'Fields'
Open the Product Type Field:
Click the green + to add a new option:
Once you do, click 'Save & Close'
And then click 'Publish All Customizations'
Your new product type will now appear as an option in the drop down product type field on the product record: