Given that I don't know how to read codes, how do I know that the smart contract shown on github has what the ICO states in the whitepaper?
You can either find some trusted third party reviewer that checks the smart contracts' source codes as a part of his reviewing routine or you have to learn to read Solidity yourself. By the way, that second option is not that hard as it might seem at first glance. I don't have much programming experience either, but after learning some basics I find Solidity source codes very easy to follow. And learning something new is almost never a bad thing. Just look at it as another form of investment, which might reap some benefits in the future.