My will.. Incase I die

Does anybody here have wills. If so how do i file or make one. I want to be able to give my child to my mother or brothers incase I die. My sons father has never been in the picture never helped out but he's name is on the birth certificate. My mom has been there for my son since day one and my son even calls her mom more then me. Can someone please give me info on this. I know it's extremely important if you have kids and not knowing when we going to pass away is scary not to know to who our children will go to if we do not have a will.