Bakers make bread and sometimes cakes and pastries either by hand or with the use of catering machinery.
Chefs prepare, cook and present food, they sometimes specialise for example pastry chefs. Most chefs work in restaurants and cafes.
Waiting staff serve and supply customers with food and drink when instructed. They mainly work in restaurants and bars.
Cake decorators are actually artists who create beautiful cakes that not only look good but also taste nice. They are skilled in using icing to make (at times) very intricate designs.