Rocio --
Each of your team members will need a Project Essentials license. After obtaining their licenses, you (or your application administrator) will need to add them as resources in the Enterprise Resource Pool and add them to the Team Members security group in Project Web App. Once done, you will need to add those team members to your project team, and then you will need to assign them to tasks. After doing this, you will need to publish your project. Your application administrator can configure Project Online so that your team members will report their progress on either the Tasks page in PWA or the Timesheet page in PWA.
Hope this helps.
