Can anyone give me a good source to learn Convolution theorem? I was trying to solve the problem Fuzzy search when I read some solution they all talk about convolution. I understood the process ( u just reverse one polynomial and then perform FFT but I don't understand why it works.[ I tried to read from Wikipedia but talks about time domain, frequency domain etc so didn't get anything there.] Thank in advance.

A brief source:

https://www.dsprelated.com/freebooks/mdft/Convolution_Theorem.html

A more detailed source:

http://cdn.intechopen.com/pdfs-wm/41657.pdf