Hi there are some amazing tutorials that will guide you step by step but a couple of things to note:

1. When you set one up it is ‘off’ your personal profile with you as the owner and admin for that page
2. It is wise to set up at least 1-2 others as admins in page roles, even as back up because if you get hacked and someone does something against FB rules your profile will suspended or worse deleted and all your pages and groups with it, with others as an admin you will have them as back up so you don’t lose your following etc
3. Make sure you set your page up for the intended purpose and become familiar with settings and permissions, you can do things like set up automatic messages when people message your page. It is always good to have your website or other means of contact there so people can get in touch with you.
4. If you link up your Insta and FB then you can simultaneously post but audiences and capabilities are a bit different across the two platforms, so you the way you post on Insta may have more options or need some more detail on Facebook.

Some audiences are across both but the marketing brain is different in those spaces, what people are looking for and how they interact

My advise is based on years of building and managing Facebook pages for clients, I currently manage 6 pages for very different busiensses

This how to set up is the best place to start

https://www.facebook.com/help/598453443693392?helpref=faq_content

Nga mihi

Jen