Think about how your website different from other social media website? Is your user-friendly and providing more advance features then other? If yes, then draft detail document, create videos, and plan for marketing strategy.
Initial basis, you will need to active your website and connect yourself, employees, family and friends for test purpose. Receive feedback and suggestion from their and implement if applicable. Once they are connected, they will promote your business and will discuss with his/her friends. When your website is live then start email marketing, content marketing, video sharing, etc.