It seems there’s a lot of miscommunication. When that’s the case, the only real answer is to have some frank conversations. Hopefully when you started, there was a timeline set out for check-ins or reviews. They would be a great opportunity to take some of these issues to your manager. Use that time to sit down and clearly define your role. With that in writing, you can clearly demonstrate what support you need in order to do it. Don’t assume they’re aware of all the issues you’re facing.
If that doesn’t work, perhaps go to those who were involved in hiring you. Let them know what your experience has been like so far, I’m sure they’ll be interested to know.
They say it takes 3-6 months to settle into a new job. It’s bound to feel overwhelming while you get into your rhythm. It’s worth remembering that your team might be experiencing that settling in period too, especially if they haven’t been told they’re reporting to you. Good working relationships take a while to form naturally, so try not to put too much pressure on them functioning at 100% just yet.
Ultimately, if the role isn’t what you signed up for, you should take a step back and check that this is what you want. If they had posted an accurate job description, would you have applied? There’s always a chance to step away if you’re unhappy.