This is an Arma 3 tutorial on how to create custom sound clips, including how to edit.
Dropbox link to mission folder sound files:
https://www.dropbox.com/scl/fi/tot26h...
The first place I look for sounds:
https://freesound.org/
Download Audacity sound editor:
https://www.audacityteam.org/download/
You can make requests + more on our Discord channel:
/ discord