Answer by taking a quote from the following article:

William Morris Hughes,  (25 September 1862 - 28 October 1952) was an Australian politician who served as the seventh Prime Minister of Australia, in office from 1915 to 1923. He is best known for leading the country during World War I, but his influence on national politics spanned several decades. Hughes was a member of parliament from 1901 until his death, the only person to have served for more than 50 years. He represented six political parties during his career, leading five, outlasting four, and being expelled from three.

In 1919 Hughes, with former Prime Minister Joseph Cook, travelled to Paris to attend the Versailles Peace Conference. He remained away for 16 months, and signed the Treaty of Versailles on behalf of Australia - the first time Australia had signed an international treaty. At Versailles, Hughes claimed: "I speak for 60 000 [Australian] dead". He asked of Woodrow Wilson; "How many do you speak for?" when the United States President failed to acknowledge his demands. Hughes, unlike Wilson or South African Prime Minister Jan Smuts, demanded heavy reparations from Germany, suggesting a staggering sum of PS24,000,000,000 of which Australia would claim many millions to off-set its own war debt. Hughes frequently clashed with President Wilson, who described him as a "pestiferous varmint". Hughes demanded that Australia have independent representation within the newly-formed League of Nations. Despite the rejection of his conscription policy, Hughes retained popularity with Australian voters, and in the Australian federal election of December 1919 his government was comfortably re-elected. At the Treaty negotiations, Hughes was the most prominent opponent of the inclusion of Japan's Racial Equality Proposal, which as a result of lobbying by him and others was not included in the final Treaty. His position on this issue reflected the general mindset of "racial categories" during this time. Japan was notably offended by Hughes's position on the issue. Like Jan Smuts of South Africa, Hughes was concerned by the rise of Japan. Within months of the declaration of the European War in 1914, Japan, Australia and New Zealand had seized all German territorial possessions in the Pacific. Though Japan had occupied German possessions with the blessing of the British, Hughes felt alarm at this turn of events. In 1919 at the Peace Conference the British Dominions of New Zealand, South Africa and Australia argued their case to keep their occupied German possessions of German Samoa, German South West Africa, and German New Guinea respectively; these territories were given as "Class C Mandates" to the respective Dominions. In a same-same deal Japan obtained control over its occupied German possessions north of the equator. With reference to Hughes's actions at the Peace Conference, the historian Seth Tillman described him as "a noisesome demagogue", the "bete noir  [sic] of Anglo-American relations". Unlike Smuts, Hughes totally opposed the concept of the League of Nations, as in it he saw the flawed idealism of "collective security". CANNOTANSWER

What happened at the conference?

signed the Treaty of Versailles on behalf of Australia - the first time Australia had signed an international treaty.