Information literacy has long been considered an important aspect in school, as well as in the workplace. Teenagers are the first group affected by requirements based on information skills. Transliteracy occurs as a relevant concept to understand these information practices. Indeed, a holistic approach is needed in order to take into account the multiplicity of contexts of uses and interactions. The resarch work described here proceeds from a program funded by the French national research agency (ANR Translit 2013-2016) focusing on how high-school students (15-16 years old) manage information with all the available media and tools, individually as well as collectively. Based on ethnographic methodology, the study was carried out between November 2013 and March 2015, in five French high schools during specific learning project based activities. Findings demonstrate that activities and knowledge management on the school workplace must take into consideration complex information skills crossing personal competencies, representations, and self-esteem on one hand, school requirements and context on the other; complex social interactions during information activities; postures and spaces encouraging horizontal learning processes between teachers and students in