Go to the README to know how to use it.
If you are using Mac OS or Linux, you can install using the commands:
curl -L https://github.com/gumieri/p/releases/download/v0.3.6/p-`uname -s`-`uname -m` -o /usr/local/bin/p
chmod +x /usr/local/bin/p
If you already have an older version installed, just run:
p upgrade