How to do a mail merge in Pages

I am trying to make a mail merge document in Pages. I have tried to look into the Pages help section and also searched for answers. I came as far as being able to define placeholders. However when advised to use the Inspector to merge data into the placeholder, my inspector turns out blank with no options to merge. I am using Pages 7.2 on Mac OS 10.13.6. Am I doing it right?

Thanks