Go to the Serving tab on the left panel and click on Service Teams. Click on the Service Team the volunteer belongs to. If the volunteer belongs to more than one Service Team, choose anyone that volunteer belongs to.
Check the check-box next to the name of the volunteer. See more options appear on the top bar.
Click on Serving Journey.
You will see the Service Teams and Roles this volunteers has been serving in, past and present. By clicking on the Roles, you can view all the events this volunteers has served in that particular role.