I am the author, and I think the best way to get started is by looking at existing contracts, which are generally written in Solidity, Ethereum's language for writing smart contracts. Here are a few examples that I found helpful:

- https://github.com/etherpot/contract/blob/master/app/contrac... - https://etherdice.io/#contract - https://ethereumpyramid.com/contract.html - And of course the main docs, http://solidity.readthedocs.org/en/latest/ (see also https://github.com/ethereum/wiki/wiki/Solidity-Features)

Once you have a smart contract, it's a good idea to provide some interface to help people interact with it. There are a number of JS libraries to help you interact with Ethereum available at https://github.com/ethereumjs.