From there, select "Users" and then click on “Create” to make a new User.
Give your new User a Username (email address is easiest), add their email address, first and last name, and click on save. Your new User will receive an email with login instructions.
You must assign your new User to a group so they have permissions. Go to the Groups tab and click on a group to add your new User to the correct User Group. (Learn more about User Groups here.)
You can add that particular User in an existing Organization to which it belongs, or else create a new Organization. Further, a newly create Organization can be added to respective Organization Group in the same window (see 1#, "+Associate Org to Group" blue button after the new Organization is created).