Can anyone advise how to set this up, the readme instructions are pretty vague?

If i remember correctly this was made for

"FSPASSENGERS"

I think its still available, but unsure about if there is continued support for it.

I guess the sounds could be used in something like SLC..Self Loading Cargo.

You can still download the files and use them within Bluesky for announcements, these can be configured for different events or flight phases. All you need to do is move them to a relevant location and map them to different events in bluesky.

If you download the files you can put them in the sounds folder of bluesky and then point the different flight phases to the sound you want to play, it still works really well, however, i have replaced most of them for me as I'm using Fenix