Embedding an AppEngine App In My Website - Impossible?

First I should mention that I am NOT a developer.

I did hire a developer recently though, and he built me an app on Google AppEngine. I want to embed that app into my Wordpress website. I assumed it would be as easy as embedding a YouTube video, but it's looking to me like embedding the app might actually be impossible

Is there any way to accomplish what I'm trying to do? I want the app to appear inside of my WordPress site - you know, surrounded by my header image at the top, menu down the side, etc... I want it to appear just like any other page of my website. Also, I want to remove my app from myappname.appspot.com - I don't want anyone to be able to access it there.

I did read this - https://developers.google.com/appengine/docs/domain - and I started following those steps until it seemed like I was required to have the app appear on a subdomain of my website (i.e. myapp.mydomain.com) rather than just a regular page of my website (i.e. mydomain.com/myapp), and it started talking about domain mapping and CNAME (what is that all about??).

So, is there a way to do what I want, or am I screwed because my app was developed on AppEngine, and I need to hire someone to rebuild it from scratch using some other method?

Thanks in advance for any answers!

Please forgive me if I've posted this in the wrong section - if I did feel free to move it to the right place...

If you want to embed it like a youtube video, insert this HTML into your page:
<iframe src="***INSERT YOUR APP URL HERE***" width="500" height="500"></iframe>

Making it inaccessible on myappname.appspot.com would take more code. CNAME is a way to make your domain go to a server. See http://support.google.com/a/bin/answer.py?hl=en&answer=48090 for an explanation.