Morning @Jobpanic !
How exciting. Having just started a new job myself 2 months ago, please may I offer:
They hired you so they like you
They hired you because they believe that you can do the job
They have a gap in their organisation and need someone to fill it. Likely that people have been covering the gap and will be happy you are on board so they have less to do
So, they have positive outlook which you can mirror
Everyone (pretty much) has imposter syndrome.
Be friendly, shake hands, introduce yourself to people you meet at the coffee machine, ask who they are and what they do. Ask what the form is for lunch (at desk, in a group ?).
Apologise that you may not remember everyone's names in the first couple of weeks.
Have your 'me pitch' ready. I.e a potted sentence to say who you are, where you came from, what your role is and how exciting it is to be here.
Take notes of key peoples names. Ask for introductions.
Spend time with your boss to confirm exactly what your role actually is and what the actual issues are - it's likely they showed a better picture than reality 😬 ask him/her what success looks like for you and them (you'll probably already know from interview, but confirm anyway). Initially ask for regular meetings /feedback from boss so you can make sure you are on track. Ask them who you need to get close to /emulate / get coaching from.
Find out about internal support such as IT, HR etc. And if there are any communication tools like Teams. Join any social channels they have.
If you are taking this opportunity to reinvent yourself a bit, go for it with confidence.
Most of all relax, concentrate and enjoy the new job. Exciting!