In the event that a Project Manager is already in the process of creating a project plan and they need to replace already selected resources, or simply need to add new ones to their team, they can do so directly from the project plan.

To add a resource to your project team directly from the Gantt chart view,

Click on the insert resource icon on the tool bar

Select the new resource to add from the "Insert new resource" dialog box and click OK.

The new resource will be added to the list and available for task assignments