While adding an individual product, there is a field for product visibility. Keep in mind that your product prices will not be revealed to companies you are not connected with - prices are visible to connections only.
The privacy settings are defined as:
Public: Any user can see this product, logged in or not.
Community: Only logged in users who are part of the community can see this product
Connections: Only connected companies can see your products
If you are in the Showroom Management page, you can adjust product privacy without clicking into an individual product.