Information on how how freelancing works

Hi,

I've recently been offered a freelance dev role. I'm excited to give freelancing a try as I've never really done it before. However, as I've not done it before I basically have no idea how any of it works. Even basic stuff I'm clueless on. Does anyone know of any good resources so that I can take a look at to give me an idea of the basics?

I'm in the UK if that makes any difference.

Any help would be greatly appreciated.