What do I need to do if the defendant has replied to my claim on a civil suit?

You need to hire an attorney to represent you. No attorney can tell you how to litigate your case.

If you are in a small claim, you need to exchange that information. If you are handling a regular lawsuit pro se you might want to seek the pro se help desk.

Would you strap on football pads and walk onto a field to play pro ball? You need a lawyer. Get a copy of the court rules and follow them.

I presume you mean you must provide the "defendant" with a Witness and Exhibit List, as you said you filed the claim, so you would be the "plaintiff"? You need to read your local Court Rules and/or the Michigan Court Rules and/or any Scheduling Order issued by the Judge re: what is due, when and in what format. You then need to comply with the Rules for your submissions to be proper. Typically a Witness List needs to identify any and all witnesses you may call at Trial. The applicable Rules will indicate whether you only need to list them by name, or if you need to include addresses, or summaries of their expected testimony, etc. Typically the same is true of an Exhibit List, usually it is simply identifying, with some specificity, the documents that you intend to introduce into evidence at Trial. Again, some local rules can require you give the date of the document, the # of pages, the author, etc. and some courts will require you to provide copies of the Exhibits with the list, some will only want you to provide copies "x" days before Trial, etc. Most Judges require a copy of all Exhibits before the Trial, but not necessarily when you file your Exhibit List (again, read the rules). So there is not just 1 rule on this, which is why you need to research and read the applicable rules.

Have to provide copies.

Depends what court you are in. I would send all to be on the safe side. You said plaintiff, you meant defendant.

Sorry; far too complex to respond properly.

If you've never done this before, don't expect to win. Go hire a lawyer if you want to win.