Disclaimer: Participation in any SNS is at your own risk.
Once you have acquired SNS tokens, you can lock them into SNS neurons and create a proposal or vote on one. If a proposal gets adopted, the code of the SNS DAO or the dapp it controls is upgraded. Depending on the SNS configuration, users who vote may be rewarded with additional tokens for participating in governance. If you want to get more deeply involved, you can also suggest feature updates through proposals to improve the dapp controlled by the DAO.
SNS works very similar to the NNS, however each SNS DAO can configure their parameters differently. Once you have locked your SNS governance tokens into SNS neurons for at least the minimum required time, you can participate in voting. Depending on the configuration voting may reward participants with SNS governance tokens.