my car wont start and idk what it means

so im a girl so my knowledge is not the greatest about cars but ik a little. i drive a Lexus RX350 i think 2014 model. my amplifier was not working before and my dad took it and “fixed” it but now it still doesnt work and sometimes audio comes out for a little bit then its back to not working. i tried turning my car on but this weird sound was coming out and my dad took a look at it and called some people and he told me it could be an “electrical” problem from something called the dynamo. i dont really understand what the stuff means and i would like someone to explain it to me and also is that dynamo actually the problem or is this an engine thing? helpppp