standard disclaimer about financial advice, etc., applies - but in my own opinion, the value of the current Steem and SBD tokens is going to plummet after the hardfork happens. Quite a few Steem whales have publicly stated they will be selling off their Steem and moving to the Hive chain (@blocktrades being probably the most prominent, and he is one of the largest stakeholders on Steem). It isn't so much about abandoning money, as preserving the value that you worked so hard to get. Again, my own opinion, and I don't have a crystal ball - but I think Steem users who do nothing and just hold on to their Steem tokens are going to see the value of their Steem wallets crash to basically nothing over the next 3 months (the period of time it takes to power down a Steem account / 13 weeks).
As far as how to convert your Steem / SBD to bitcoin or fiat, you have to create an account at an exchange that lists Steem / SBD first (this will require KYC, usually the process involves both submitting your ID and a selfie). Once you have an account, then you deposit Steem at that exchange (transfer your Steem / SBD to the address the exchange gives you for the deposit, with the memo that the exchange gives you to direct it to your own account at that exchange). The exact process / buttons to press is going to vary some from exchange to exchange. You can find a list of exchanges that trade Steem here: https://coinranking.com/coin/fXGcu_EzDgP25+steem-steem/exchanges
I personally use bittrex.com .
Once you have your Steem / SBD on an exchange that lists Steem / SBD, you can trade it for bitcoin. From there you can decide if you want to keep it in bitcoin, or if you want fiat you can convert bitcoin to fiat. I don't believe there are any exchanges that allow a direct Steem to fiat trade without going through an intermediary step like bitcoin. Let me know if you have any specific questions about that process.