Your administration domain owner will need to install and give access to users on your GSuite domain. Once you have installed Gantter to your GSuite, you can purchase subscriptions for the seats you will need licensed. 

This is how you can do that:

1. Click on "Manage Subscription". This can be found in the menu on the top-left of the home screen or under the "help" menu in the editor. 

2. Click on "Buy & Manage Subscriptions"

3. Click on "Buy More"

The following are the steps to assign users to the licenses that you purchased:

1. Click on "Manage Subscription". This can be found in the menu on the top-left of the home screen or under the "help" menu in the editor.

2. Click on "Manage User"

3. Enter the email address of the user you would like to add and click the '+' button

4. Then click "Apply Changes"