Sound comparison in C#

Question

Good day. I just want to ask a question about our thesis. We were suppose to make a program using c# that can detect a snare drum sound from a song being played. I thought of the idea as comparing the frequency of the default snare drum sound with the song. As soon as it detects that it has the same frequency then it will emphasize the part where it is detected. The question is:

1. How am I going to identify the frequency of a sound using Fast Fourier Transform (FFT)?
2. How am I going to compare them?

Every response or comment is much appreciated. THANK YOU!