See Sending Reference Check Letters for how to set up the mail merge settings. Save those settings under a useful name: we'll need those in the scheduled task that automatically generates and sends these e-mails going forward.
See Also
Reference Checks and VSys Live
Reference Check Certifications
VSys Live Applications - Providing References
VSys Live Applications - Reference Responses
Reference Check Letter Templates
Reference Check Scheduled Tasks
Completing the Reference Check Online
Reference Check Results