MADISON, Wis. (AP) – State utility regulators are planning a free seminar to help attorneys and the public understand their procedures.   Public Service Commission officials have scheduled the seminar for April 10 at the commission’s Madison headquarters. The agenda will include discussions on PSC rules, compliance with commission orders, how to use the commission’s electronic filing system and a question-and-answer session.   The seminar is expected to run about an hour and a half. Anyone interested in attending must register by March 29 through the commission’s website.