Complex sentence: The award is for the first book of history by an an Australian scholar and is awarded biennially for first books published in the preceeding two years with awards presented t the AHA's National Biennial Conference.
Split into simpler sentences: The award is for the first book of history by an an Australian scholar. It is awarded biennially for a first book published in the preceeding two years with the award presented at the AHA's National Biennial Conference.