The Members tab on the settings page contains a list of members and user groups in the organization.

In the Members section, you can view the linked list of all the people associated with an organization. If you have the appropriate permissions, you will be able to edit the default access for all members and add or remove members from the organization.

In the Groups section, you can view created within your organization. You can click through to see the group permissions and members in each group. If you have the appropriate permissions, you can edit the groups and create new ones.