WMM is a linear editing program and although it has some PIP (picture in picture) effects what you are after requires an editing program that allows multiple video tracks like Adobe Premiere or Sony Vegas.
I believe you are talking about Pwolf's "this time"?
In which case you should read the video description on how he did it, however you don't have to 3D render a TV to do this in it's most basic form (it will not be the same as king pwaffle's vid but it will get the point across) just premiere or vegas or ae.
Long story short, you cant do it in WMM (unless you are an xml god and even then
) so dump this shitty program and get something better