Transcode Apple Lossless to AAC 320

[Desneige08]

Hi: I know how to get into the properties to change the default Mp3 128 setting for each song, but I want to know how to change that default to AAC 320. I have searched high and low for answers but since I don't know how to code, it's all too confusing to me. Can anybody shed some light on how to do this for me since I am not a fan of Mp3 formats. Thank You.