19 year old trying to buy a new/used car

Well my whole life I was never taught anything about finances or anything like this. I have been trying to do it on my own. But I have a car (POS) it's payed for and everything. But it's gonna be dead soon. And I have not one clue on how to go about getting another used car. I know I could use my car as a down payment? Can I also find places that dont look at credit because I have none. Truly I just dont know where to even start, so please help a youngin out!