How do your write an affidavit that will assist you in custody of your child?

An affidavit is a statement made under oath that the content is true and factual to the best of the knowledge of the person who is giving the information. Such a statement must be made according to the requirements of the law of the state in which the attestor resides. Custodial issues are generally addressed by the court at the hearing and affidavits/ witness statements are only allowed in unusual circumstances (the testifying person is disabled and cannot appear and so forth). A parenting plan is a different matter, it is a court document that is, in some US states a requirement and is always presumed to be taken under oath with the penalty of perjury applicable.