BROKE CUSTODY BATTLE ADVICE

Somebody, PLEASE! Help me with any advice you have on custody battles! Any divorced or soon to be divorced mamas out there that have been through a custody battle with their (ex)husbands, PLEASE HELP ME OUT!! I need advice! How do I get help? I haven’t been able to get a job because I’m a full time mom so I have no money to pay a professional lawyer... I need to know what precautions I should take in order to help myself out in the event that my soon to be ex husband tries to take my son away from me.