Easiest way to send Bulk Emails is by creating a new list and adding the contacts to the new list. Or you can go directly to the companies profile page and send a bulk email to all the contacts that are linked to that company. You can only send 100 emails at a time. 

or Contacts page

2. Click on the select all box, then click "Email"

3. Compose your bulk email then click on "Send" once you are ready to send out your emails or click "Schedule" if you want to have the email sent on a different date and time.