Project roles - don't write the word "me" instead write your name, since we're writing this all in third person. So for example, your role is Project Manager and also Team Lead. You can put my role as Project Advisor. Put spaces for Quality Assurance role (since you mentioned testing) put currently your name there, later we'll see when someone else joins regarding that role.
Milestones - these should correspond to your phases, so next to the phases, there should be the dates for the milestones.
Dear @valentinacupac , I have read the following pages: https://www.projectmanager.com/blog/how-to-create-a-project-charter https://project-charter-template.casual.pm/ http://continuingprofessionaldevelopment.org/how-to-write-a-quick-and-easy-project-charter/