There are quite a few premade automated message templates in your Check Cherry account. To use the one to request a review after an event, simply go to:
Manage - ->Automated Messages
Click on New Automated Message
Select the Pre-built templates button under the one that says "Scheduled Date"
Choose the one with the subject line "Send the customer an email 2 days after their event asking for reviews"
When you click View Template, you can edit the message, apply it to the packages and/or brands you want it to apply to, and choose whether to send the messages automatically or send them to a review queue.