how do I file for a divorce and kids custody.

If you own a home and have three children together, this is not a do-it-yourself project.  You need to hire an attorney experienced in divorce law in or near the county where you live.If you are awarded the home, there may be an owelty lien established if one of you has to buy-out the other's interest in the marital residence.  There almost certainly will need to be a special warranty deed of either of you keep the house.  If you have a mortgage, you will likely want a Deed of Trust to Secure Assumption to keep the current loan at the current interest rate.The more items you and your husband can agree to in advance, the less an attorney will cost.  If you can agree on most items now, you might be able to get an attorney to advise you on those things you haven't thought about and to complete all of the paperwork for $5,000 or so.  If there are major areas of disagreement, budget more for legal expenses than that.