First, find and download any chosen hitsounds. Hitsounds must be in the .wav format.
Go to this folder \AppData\Roaming\distort\cs2\sounds and place your chosen sounds.
Use the following file names:
hs.wav - headshot sound
hit.wav - hit sound
2.wav - second kill
3.wav - third kill
4.wav - fourth kill
5.wav - fifth kill
Sonar.wav - sonar sound