The Install platform works seamlessly with our Lite and Enterprise Platforms, but is sold as a separate subscription.
To add access to the Install Platform, just go to Settings > Team and select the team member that you'd like to add PM for.
You will see an overlay with that user's permissions. Select one or both of the permissions at the bottom under the "Project Management" heading.
Note that selecting these options will automatically initiate a payment for the Install Platform. (If you are in the middle of your billing cycle, the payment will be pro-rated.)
To remove the Install Platform subscription, just deselect the boxes under the "Project Management" heading.