Anyone in academic research able to give a summary of how grants are decided? I'm under the impression that most science research is guided by military, corpor

Anyone in academic research able to give a summary of how grants are decided? I'm under the impression that most science research is guided by military, corporate, and imperial needs. And, far less pure science gets funded just to empirically understand the universe. It's a horrible shame in my opinion. Can't crowd funding come into play somehow? I'd love to donate money to scientific research. But, how is it possible for a layman to validate the 'real science' from the quakery?