You can start by joining the VIVA chat at https://chat.vivaco.in . If you would like to invest in VIVA by becoming a crownholder, there will be a public ICO launching in the near future. There may also be one more auction round on Steemit, but I don't think that's been completely decided yet. You can keep up-to-date on the latest news & announcements through the chat channels.
You can also sign up to join the beta testing of the TradeQwik exchange, which is the only place where the few VIVA coins currently in existence can be bought & sold: https://live.tradeqwik.com/