After starting a marketing agency from scratch and growing it for over 6 years, Doru Catana realized that the only way to reach more businesses and scale his efforts is through online courses, thus the pursuit of delivering the best content possible that helps professionals execute their goals started.dealing with all aspects of Excel from basic competence to advanced data analysis. He is able to bring these years of practical experience to our Advanced Excel course, ensuring that the course explains advanced concepts clearly and concisely, and with real, practical applications and even the occasional joke.