Within each Teamwork product, you can enable Teamwork Spaces for your site through the site settings.
Teamwork
In Teamwork, select the Integrations tab in your site settings and scroll to the option for Teamwork Spaces. Click the Enable button to enable it for your site.
You can also enable Teamwork Spaces through your Teamwork product switcher.
Teamwork Desk
In Teamwork Desk, go to the Apps section of your site settings and click Enable under the Teamwork Spaces option.
You can also enable Teamwork Spaces through your Teamwork Desk product switcher.
Note: Enabling Teamwork Spaces from one of your other Teamwork products will automatically initiate the 30-day trial period.
For more information, see: Understanding User Permissions and Access