What legal stuff you need to do will depend largely on what country you’re in, the legal jurisdiction. Are you doing this just for fun? Then probably very little. Are you hoping to make money from this? You might want to set up a legal entity, a company that owns and publishes the website, probably something that limits your personal legal liability in case someone decides to sue you. Speaking of which, you’ll probably want to become very familiar with legal requirements for libel/defamation where you live, as well as where you can legally take photos/videos without permission and if you need someone’s consent to publish their image.

In registering your company you’ll also need to register with the tax authorities. Keep in mind that there are usually fees involved with these registrations, so you’ll want to have a plan to hopefully break even if not turn a profit, unless you don’t care about losing money.

You’ll probably need to have some legal documents like Terms of Use, Privacy Policy, Cookie Policy, etc. Even if it’s not legally required where you are those are good to have. If they are required you’ll want to be sure you’re familiar with those requirements and what they mean, such as what data you collect and how you safeguard it. I’ve found this write-up informative; it’s U.S.-focused but should at least give you an idea of the kind of things you need to consider if you’re creating a website with a significant audience. You might also want an explicit statement about AI/LLM training with your content, and be familiar with copyright laws in your country; do you need to register/submit your content for protection?

That’s not necessarily exhaustive, but probably a good starting point. Depending on how serious this venture is for you it might even be worth consulting with an attorney. Most news organizations have some level of ongoing relationships with an attorney or attorneys, either in case they are sued or perhaps they need to sue for open access to government records or similar.