A license must have permissions on a product to use it.

Complete the following steps to set product(s) permissions for your license(s):

Select in the tree the license(s) for which you want to assign product permissions.

You can select multiple entries by pressing the Ctrl key  of your keyboard.

Click on the Product permissions button.

The list on the left shows the products available. 
If you've selected only one license in the tree, this list shows only products for which the license doesn't already have permissions. If you've selected multiple licenses in the tree, it shows all the products.
If you've selected one license in the tree, the list on the right shows the products that are currently authorized with the selected license.

Select one or more products in a list and drag them with your mouse to the other list to change permissions.

When you have selected multiple licenses for permissions, you have the choice to Replace all permissions or Add to existing permissions.

Click Apply to validate your changes.

Note: Keep in mind that if you have multiple licenses registered with the same email address, you will not be able to give them a grant to use the same product. This ensures that a user is always able to retrieve the right Activation Key from any of your product, using his email address. This will also prevent users to register multiple times for a trial license with a specific product.