slategrey's audition guide I found in the comments explained a bit about this. (It has more than just audition stuff). So I haven't done it myself yet (I'm working through the routes slow but surely), but it has a detailed description in here somewhere https://docs.google.com/document/d/1P6iYaiVrfa9TLpGbv7B51TocGv3zhcPUK89HzrbKyIw/...