Here is a procedure about adding another account to the organization:
The owner of the organization must log in to the Terminal, then add another account to his organization by:
going to "IAM & Security" > "Users & Roles"
pressing "Add" and entering a valid email address (an invitation will be sent there)
granting the permissions.
After that, an invitation will be sent to the email address, containing the invitation link. Please press on the link, then finish the registration, tick the box that you agree with our TOS, and you are good to go!
Easy as that.
Accountant - deals with Invoicing,
Operator - deals with servers and services,
Owner - all permissions.