How to buy omni coin before listing?

I'm curious, how does one go about purchasing Omni Coin before it's officially listed on an exchange? Is there a specific process or platform that's typically used for pre-listing purchases? And what are the potential risks and benefits of investing in a coin before it's listed? Could you walk me through the steps and considerations I should keep in mind if I'm interested in acquiring Omni Coin before it becomes publicly available?