Abstract: Children and adolescents acquire different habits as they grow up. Some of these habits are closely related to health, so acquiring healthy habits can greatly help them lead a healthy and peaceful life in the future, while bad habits can be detrimental to them. For that reason, it is necessary that from the different educational institutions, we help these young people in the acquisition of these habits. The aim of FITeens (Promoting physical activity and healthy habits in sedentary teenagers) project is to pilot an entertaining and engaging educational intervention targeted at teenagers to promote physical activity and healthy habits This first result of the project consists of a comprehensive set of ideas, resources, practices and some examples for Physical Education teachers that will cover the different key behaviors that increase the risk of chronic diseases (physical activity, sufficient sleep, moderate screen time, alcohol and tobacco consumption, and healthy food intake) that can be incorporated into their teaching practice. This toolkit consists of 3 different modules: 1. High schools as effective settings to promote healthy lifestyles. This module covers the importance of schools in the acquisition of healthy habits by adolescents. 2. Motivation as a key to physical activity promotion. This module focuses on the importance of motivation in the acquisition of healthy habits. 3. Health-related behaviors in young people. This module will focus on the key health-related behaviors mentioned above (physical activity, sufficient sleep, moderate screen time, alcohol and tobacco use, and healthy food intake), describing each of them in depth. All of these modules are dedicated to the different health-related behaviors mentioned above. Each of them will have a theoretical explanation, explanatory videos, infographics and learning situations that will support Physical Education teachers in acquiring a broad knowledge of how to get their students motivated to engage in physical activity and acquire healthy habits, making them aware of their importance.