Before sending a template, make sure you have your WhatsApp Business API channel connected and templates with variables created. When you are sure that everything is ready, follow the procedure:
1) Go to ChatApp Dialog and open the dialog you want.
2) Click on the "+" in the message entry field.
3) In the opened window, click "Send Template".
4) From the menu on the right, select a template with variables.
5) Insert your value in the variable field.
6) Enter the phone number in the "Phone" field.
7) Click on "Send"