Could you be more precise about your first question.
as for the second question AM Modulation is easy to generate : just google AM Modulation circuit
finally, it appears to me that you haven't yet understood the concept of modulation, and as for radar system it's not just about modulation, it's a complicated subject that involves a great deal of communication, Antenna design and signal processing.
But as my teacher once told me, what you know is easy .. what you don't know is difficult.
My advice: Try first to understand the basic concepts and get the big picture.
Regards