@gulflee, sorry for the delay in response. The current version o Media-Tags does not follow standard convention on the template hierarchy. Mainly because Media-Tags was written a few versions before the core support. I do plan to correct this in upcoming versions.
For now you need to name your templates as
mediatags-<term>.php where ‘<term> is your archive term like ‘flowers’, ‘books’, etc.
Also, by default if your theme has an archive.php template it will be used by default.