ONCODIR aims to increase the awareness of citizens in Colorectal Cancer (CRC). To do so, a personalized citizen behavioural intervention system (NELI), a mobile app for use by the citizens has been delivered. This video explains how to set up and use the app during a study, which takes part in the ONCODIR project. It further informs about creating an account, verifying the user’s email, accepting terms, completing initial questionnaires, and setting up an activity tracker. NELI tracks various health metrics and allows the logging of clinical test results.