Lets say the new car cost $30,000 can I put everything in financing?

If not how much cash should I have to pay a minimum downpayment?

And how much cash do I need to bring extra to pay for insurance and other stuff before I can drive the car off the dealer?

I'm new here in the USA and as such I don't have a credit history yet, could my brother stand as my guarantor?

Thanks so much guys for any advices you can give.