To control who has access to an organization, and what they have access to, go to the "Users" section of the web UI.
Adding users is done by email address and requires the user to already have a limacharlie.io account.
The first user of an organization is added with Owner permissions at creation time. Owner permissions give full access to everything.
New users added after the creation of an orgnization are added with Unset privileges, which means the user is only able to get the most basic information on the organization.
Therefore the first step after adding a new user should always be to change their permissions by clicking the Edit icon beside their name.
Permissions can be controlled individually, or you can apply pre-set permission schemes by selecting it at the top of the dialog box, clicking Apply and then clicking the Save button at the bottom.