How does BinaryBuilder work?

Can BinaryBuilder.jl deploy its toolchain building and vm locally and Id like to test building and deploying a jll locally and test vendoring it across another platform but im not sure if I need to CI push a deploy/recipe to BinaryBuilder or how that works? If I install the entire stack whats the limit of local deployment and testing with vm toolchains that I can do? if I deploy a vm to run the binarys can BinaryBuilder vm the toolchain building with a set of rules and provide seperate or a sing...