Added instructions for audio transcoding
I know that @LightArrowsEXE already wrote this, but his instructions are not in line with what was written on the "Preparation and Necessary Software" site (using ffmpeg flac instead of libflac), he repeated a lot of things already written in the aforementioned site, and also added a lot of information that are completely unnecessary, like explaining the difference between lossy and lossless (basic knowledge that is IMO not needed in this guide, plus it's also mentioned in "Preparation and Necessary Software") or comparing file sizes for different flac levels, or explaining what "FLAC" means, lol. I also disagree with some of his statements, which I commented in his pull request #21.
I would suggest running flac with -V just to be safe.
Also it would be pretty nice to expand on multichannel files a bit because certain channel layouts will fail to encode with the current examples.
i can help
here #62