What did Britain want out of world war 1?
money, power, to protect France and russia from German and austria-Hungary=)
Great Britain entered World War 1 on the 4th August 1914, by the 12th August 1914 France and Britain had declared War on Austro-Hungary. Britain entered World War I because Germany invaded Belgium to get into France easier. Britain basically said "Belgium is our ally, and if you invade them we will declare war on you".
Beligum went to war with Germany because Germany's plan was to cross or go throughout beligum to attack France from all angles. Belgium had told Germany not to come through because they were a neutral country and didnt want to get involved in the war. So since great Britain and Belgium were in an alliance Great Britain eventually got pulled into the war. Hope this helped!