send email automatically when opportunity stage is closed

send email automatically when opportunity stage is closed

I cannot figure out how to send an email to a contact based on their opportunity stage set to closed. I can set automation in motion but when I select the email It is looking for an email based on the Opportunity module as opposed to the contact module. This makes it difficult as I cannot address the email individually to a contact automatically. 

Using Enterprise edition CRM. Also It may be important to note that we do not use Accounts as we are mostly a residential company. Unless someone has a better suggestion for how to integrate accounts into a residential setup, the whole category seems redundant.