Editing Garry's Mod Video

I recently got Garry’s Mod during the Summer Sale, and I am currently learning my way around everything. Eventually I want to start making some videos. I know they won’t be amazing, but I want to make sure I know what I am doing before I start making videos. The main thing I am wondering about is how they edit the audio in some videos (example: http://youtu.be/JlwHP1h54I8). My guess is that they use something like audacity to edit audio until it sounds good, but I cannot find any tutorials and want to be sure.

Thank you for helping :slight_smile:

Just cut out every single word/letter that they are saying and match it togethor