Adding the Event Date into my Email Reminder template

The Email Builder cannot use data from the Organization Event Object. Therefore, if you want to include the Event Date and Time in your confirmation email, you need to create the email in the Salesforce Classic. You should use the Start Date and Time field:
 

1. Login to Salesforce and Switch to Salesforce Classic.
2. Click the Email Content tab.
3. Click Email Template Designer.
4. Click New Template.
5. Compose your message and place your cursor where you want the Event Date/Time to appear.
6. Select the following:
   • Email Folder  = Event Email Templates
   • Merge Object = TargetX_Eventsb__OrgEvent__c
   • Merge Field = TargetX_Eventsb__Start_Time_TZ_Adjusted__c
7. Click the Insert Merge Field button.
8. Click Copy Text from HTML to Plain Text.
9. Save your changes.
10. You can now assign the template to your Event!