This document provides a user guide for a portal called U@MareNostrum that aims to involve citizens and local actors in water protection and management decision making processes. The guide outlines the different sections and tools available on the portal including forums, petitions, letters, surveys, maps, calendar and more. It describes how users can register and login with different user types, search and navigate the site, participate in discussions and processes, and utilize the various features. The goal is to support stakeholders in identifying issues and providing input to help design environmental policies for their region.