It's not exactly a walk in the park, but it’s doable if you’ve got some tech chops and a solid community backing you. First off, you’ll need to grab the Steem source code from its https://github.com/steemit/steem. From there, you’ll have to tweak the code to fit your project’s needs, think changing the name, tokenomics, consensus rules, or whatever else you’re envisioning. This is where the dev skills come in heavy; you’ll need to know C++ and be comfortable with blockchain architecture. Once you’ve got your custom chain ready, you’ll need nodes to run it. This is where the community angle kicks in, you’ll need people to support the network by running nodes, validating transactions, and generally keeping the chain alive. You’ll also need to set up a way to distribute your new tokens, whether that’s through an airdrop, mining, or some other method.
Oh, and don’t forget about security audits, forking a chain doesn’t mean you inherit its security, so you’ll need to make sure your version is rock-solid.. Good luck, and may the crypto gods be with you!