You can send emails to your volunteer individuals or in bulk.
Go to Organizer Dashboard
Click on Volunteers tab and then under List of Volunteers select the volunteers that you'd like to send the email to.
If you'd like to send to a specific group of people, click on the filters tab, select your filter, wait for the page to reload, then click on the bulk select checkbox.
Click on the Actions tab, select the Send Email option in the drop down, then click on Run.
On the next page, you can write your message to the selected Volunteers.
Then click on Next to continue.
You will then see the preview email. Click Send when ready to send out.