I am legally married and we have been separated for 3 years now and would like to know what I need to do to file for a no fault divorce

To obtain a divorce you must file a Complaint for Divorce, have it served on your spouse or have your spouse sign a waiver of service.  Then you must provide the court with a proposed Divorce Order and complete a final hearing, which can be done in court, by deposition, or affidavit.  Because of all the things that can be done wrong at any stage of this process I highly recommend that you hire a lawyer to do it for you.  You should be able to find a lawyer to do it for a reasonablel fee.  For instance I typically charge a $750 flat fee if there are no issues of support or property.  People hire me all the time to fix the mistakes they have made on their own and it is always more work than if they had just hired me in the first place.  We usually have to redo everything they have done and start over, as well as dismissing or amending the current case, which create the extra work.