Nazis were the largest single party.
Hitler demanded the post of Chancellor from the President. Hindenburg grew suspicious of Hitler and refused.
He allowed the current Chancellor to carry on and used his emergency powers to allow Von Papen to try and solve the unemployment problems.
Role of Von Papen
Von Papen was soon in trouble however he had virtually no support.
Von Papen lost his place as Chancellor, however he remained as Hindenburg's advisor.
Role of Von Schleicher
Hindenburg chose Von Schleicher as Chancellor.
Within a month he was forced to resign.
Hitler was offered the role of Chancellor as Von Papen and Hindenburg thought they would be able to control him.
Although, later events proved they were wrong.