How to buy sui before listing?

Could you elaborate on the process of acquiring SUI tokens prior to their official listing on a cryptocurrency exchange? As an investor, I'm particularly interested in knowing the steps involved, any potential risks, and any legal considerations that I should be aware of when engaging in such a transaction. Additionally, could you provide any insights into the benefits of purchasing SUI tokens before they become publicly available on exchanges? Lastly, are there any reliable sources or platforms that I could use to facilitate this transaction safely and securely?