Help with variables & templates?

[AFemaleProdigy]

I am trying to add a new template called mybannerads which will obviously be a new template that can be easilly edited with banner info. I want to be able to place $mybannerads throughout other templates such as FORUMHOME.

I created the new template in admin cp, which then shows under "custom templates". But when I try to use $mybannerads in FORUMHOME just after $navbar, nothing happens. Nothing shows up.

I am totally winging it on this so forgive me if it's something simple. Can anyone tell me what I am doing wrong and how to make this work? Thanks!