HI!!!!!!!!!!

Sorry for the noob question, but I was wondering how to use mt5 files in poser.  I noticed that I have a "material" section in my poser runtime which has mt5 files.  I tried to look up mt5 on google but found nothing useful.  I tried looking in the poser manual and found nothing useful on mt5 files.  So, if you would please help out a guy who is slow, and tell me what to do with my mt5 files.  THANKS!!!!!!!!!!!!!!!!!!!!!!!!!