You can't because you are not supposed to. Whitepapers are basically the abstract idea about the project and what makes the project good or bad or scam is how that idea is implemented. For example you can't really figure out what bitcoin potential is by reading the paper since that will only introduce the general idea about what bitcoin is trying to achieve. Not to mention that sometimes the idea is very good but the implementation is terrible/scammy like ethereum where the idea of a "decentralized smart contract platform" is good but they implemented a centralized platform for scammers with lots of protocol flaws and a mutable blockchain.