Insert Template Into Existing Template

[Rich]

I am so frustrated with the template system. I loved the days when $variable was used. I am completely lost on this new way of inserting templates into existing templates. I have read the article on variables and don't seem to be understanding it because it doesn't seem to be working for me.

All I want to do is add my ad code to the top of the forumdispaly template via calling another template.

Lets say the template were called "myadtemplate". How the heck do I get it to show at the top of the forumdisplay template below the navbar? I simply can't get it to display. I am trying to do this via plugins. I had no issues in the past when I could simply set the variable as $variable and eval the template.

Thanks for any help you can offer.