Requirements
You need to have a working WhatsApp inbox.
You need a list: How to create and manage a list (ARTICLE)
You need a WhatsApp Template: How to create a WhatsApp Template (ARTICLE)
Steps
Go to “Contacts”.
Click on a List to which you want to send a template.
Click on “Send Template” in the top right corner.
Select the template you want to send to the list.
Schedule the sending for a later point in time.
Click on “Send”.
Your contacts in the list have now received your template via WhatsApp.