The offical website of the Federal Government of Germany Make it in Germany contains a lot of helpful information about working and living in Germany.
Information about the application procedure can be found here
Please note – if you are intending to work in health care (doctor/nurse/caretaker) special rules apply. The placement will have to be done by the Federal Agency for work only. Should you intend to work in said field, it is essential to provide proof of placement procedure.
Compile the required documents according to the purpose of your stay by using the following checklists: