Personal branding is about launching oneself as a brand for achieving career goals. If you take the names of owners of some famous businesses, then they would automatically seem to you as a brand, apart from the businesses they own. It means that they themselves are brands as they have gained popularity even more than their famous-most brands.
This is kind of self-help practice in marketing and it is possible only if one has proper knowledge and directions of doing it. A personal branding trainer is a guide who gives you directions and teaches you the skills of how to project yourself as brand and become successful.