We recommend you start with simple groupings while you get used to the teams features, then add more complexity later on as your requirements change and your number of users grow. In the first instance, you should start with something basic such as general department teams, brand teams or regional teams where there are clear lines of responsibility. Or you could just start with two teams based on level of seniority or permissions e.g. an 'Editing' team that can only edit mailings and a 'Management' team that can do everything. If you don't have many users or projects, you may not need to use teams at all.