Delegates from 32 countries met in January 1919, but the conference was dominated by the Big Three - David Lloyd George (Britain), Georges Clemenceau (France) and Woodrow Wilson (USA). The delegation made presentations to them, after which the Big Three made their decision.
Negotiations were difficult. Each of the Big Three wanted such different things, that by March 1919 it looked as though the conference was going to break up.
Lloyd George saved the conference. On 25 March 1919, he issued the Fontainebleau Memorandum, and persuaded Clemenceau to agree to the League of Nations and a more lenient peace treaty that would not destroy Germany. Then he went to Wilson and persuaded him to agree to the War Guilt Clause.
The Germans were shown the proposed Treaty of Versailles, with no option for negotiation. The Germans published a rebuttal, arguing that the treaty was unfair, but they were ignored. On 28 June 1919, the delegates met at the Hall of Mirrors in the Palace of Versailles, near Paris, and forced two Germans to sign the treaty.