The concurrency part of the C-M is complicated (I think for inherent reasons), but won't be exposed to end users. It's basically defining an API that language toolchains can use to coordinate concurrency.
For end users, they should just see their language's native concurrency primitives (if any). So if you're running Go, it'll be go routines. JS, would use promises. Rust, would have Futures.
For end users, they should just see their language's native concurrency primitives (if any). So if you're running Go, it'll be go routines. JS, would use promises. Rust, would have Futures.