You can find the API reference for putFile here: https://blockstack.github.io/blockstack.js/index.html#putfile
Sorry this was not easier to find.
Instructions for setting up your own gaia hub can be found here: https://github.com/blockstack/gaia/blob/master/hub/README.md
To use the gaia hub with the cli, instructions are here: [Tech Preview] Using your own Gaia hub with the CLI
and some other relevant Q&A here: How to getFile or putFile from blockstack CLI?
Let us know if you encounter any issues or have feedback about the instructions.