private static void ViewTasksFromCheckedOutProject()
{
    using (ProjectContext projContext = new ProjectContext("https://nakkeerann.sharepoint.com/sites/pwa"))
    {
        projContext.Credentials = new SharePointOnlineCredentials("nav@nakkeerann.onmicrosoft.com", password);
        var projects = projContext.Projects;
        var projectId = "3a000b01-55f2-e811-afac-00155d24c70d";
        var project = projects.GetById(projectId);
        // If the project is already checked out, comment the below line
        var draftProject = project.CheckOut(); 
        // If not already checked out, uncomment the below line
        //var draftProject = project.Draft;
        var tasks = draftProject.Tasks;
        projContext.Load(draftProject);
        projContext.Load(tasks);
        projContext.ExecuteQuery();
        foreach (var task in tasks)
        {
            Console.WriteLine(task.Name);
        }
        // Check-In if required
    }
}