how to delete all my junk and empty my deleted files in my email in Windows 8

I know this is the dumbest question, but I can seem to delete or empty the file of my deleted or junk emails. I can individually do them by clicking the trash button, but then they go to the trash and I can empty that unless I go through each one.  I don't have time to do this on 50-100 emails a day!  I am sure there is an easy way to do this, but I can not figure it out!  I can empty through outlook but they are still in my windows 8 mail!  can someone help out an old lady?

I am really technically challenged!  thanks in advance! K