I strongly recommend you consult with and retain an attorney who handles the kind of claim you are making. A court will grant you some latitude if you are representing yourself, but not much. Not only will you need to write a motion, but you will need to write a brief in support of the motion and cite to the specific court rule from the Michigan Court Rules you are relying upon. You will need to serve it on the other side and give the court a copy. The court rules can (and I am just guessing) probably be found online doing a google search or at the State Bar of Michigan website.
A motion isn't a letter, it's a very specifically formatted document (actually, a collection of documents) that have to comply with your court's local rules and your state's rules of civil procedure, and there have to be appropriate recitations of the applicable statutes and relevant facts. The court doesn't order discovery, it's a private transaction between parties that the court doesn't get involved in unless a party files a motion to compel, and the judge issues such an order.
Your question reflects a gap in your understanding of how civil litigation works, and you've probably already made mistakes. That's not too surprising, since litigation isn't meant for amateurs, who often get creamed when they try to learn everything all at once and are up against pros. It only gets more difficult as things progress, if they do progress for you. At the very least, you need to buy a good guide that explains the civil procedure in the court you're in, and if course the best scenario is for you to hire lawyer who knows both the procedure and the substance involved in your case.
Disclaimer: I'm only licensed in CA. Please note that this answer does not constitute legal advice, and should not be relied on, since each state has different laws, each situation is fact specific, and it is impossible to evaluate a legal problem without a comprehensive consultation and review of all the facts and documents at issue. This answer does not create an attorney-client relationship.