See the FA1.2 Quick Start Tutorial for more detail.
To set up the tezos-client, follow the instructions in the Setup Tezos Client tutorial
This project requires stack@1.9.3 (newer versions have a known bug). You can install this version of stack from their github repo. You may find the instructions here helpful, though they are written with windows operating system in mind.
You can add the stack executable to your path if you want to access it as a global command (i.e. stack --version) or you can provide a path to the executable when you call it (e.g. ~/Downloads/stack --version)
stack build Note that this will take some time.
See here for the specalized multisig. Note that all commands in the readme are run from the root of the project.