Unfortunately there's no guide to walk you through the library. However, we have code level documentation in a live searchable form here:

https://www.availlang.org/about-avail/documentation/stacks/l...

There is also a strong beginning of a "cookbook" of expressions here:

https://www.availlang.org/about-avail/documentation/expressi...

There's also coverage of a sizable chunk of Avail's type system here:

https://www.availlang.org/about-avail/documentation/type-sys...