Here's some information about FINS, including that the court will appoint you a lawyer.
https://www.co.washington.ar.us/government/departments-a-e/circuit-courts/circuit-court-division-3-juvenile/fins-faq
Whatever issues you have in your home life are nothing compared to what is likely to happen to you if you run away.
My son had serious behavioral issues when he was in high school. At the age of 15 he ran away when we tried to discipline him. He became a drug addict, committed crimes to feed the habit, had several prison sentences. He's been homeless for a long time, sleeping in parking lots or in cargo containers, doing grunt labor for barely enough money to feed himself because nobody will give him a real job because of his criminal record. The really sad part - yesterday was his 50th birthday. He's never recovered from the mistakes of his younger days.
Don't say it can't happen to you. The odds are very much against a runaway teenager. Whatever your problems are, I urge you to take this opportunity to work them out, finish school, and make something of your future.