The fire in the Reichstag was used by the Nazis to justify their anti-communist propaganda. The fire was started by a Dutch labourer and communist, but it is not clear whether he acted alone. Either way, Hitler used the incident to rally public opinion against the communist left, and to justify a number of actions designed to suspend civil liberties and destroy the Nazis political opponents. Although the Nazis did not quite gain the presence in parliament they wanted after this incident, there were several factors which worked in their favour politically.
I really should point out the Reichstag fire was not the only incident that helped the Nazis gain the power they did. It was a long, slow process with many lucky turns and it's still amazing the Nazis got as far as they did. But the fire was the final incident in a long series of events that convinced many Germans Hitler was right about the communists.
There are lots of resources on the rise of the Nazis to power. Some of the more interesting books are "Rise and Fall of the Third Reich" by William Shirer, "Inside the Third Reich" by Albert Speer, and "The Hitler Book" by Henrik Eberle and Matthias Uhl. Shirer's book is a chronicled history, Speer was the Nazi Minister of Armaments and War Production, and the "Hitler Book" is taken from a work produced for Josef Stalin after Soviet interrogation of two former Hitler aides.
thank you, but thats not really an explanation.. but thanks for your suggestions anyway. can you help me understand the idea of the Reichstag fire?