It sounds as though you will be self employed and as such will be responsible for paying your own tax and national insurance. You will probably also want to ensure that your pension contributions are sorted. My husband was a sole trader for most of his working life and never needed to set up a company as such. He did cover any claims that could have arisen against him by taking out insurance never had cause to use it and you may not have to have any.
You will need to look closely at any restrictions that the company may want apply, restrictions on how and when you work could raise a red flag as some "freelance" work is offered as a way of the company manipulating your employment status thus saving them money and I have dealt with cases in which the the people concerned were in effect employees and not self employed.
Have a look at this link, which is quite comprehensive when it comes to the practicalities.
Chris beat me to a reply
but what he says is spot on.
https://www.simplybusiness.co.uk/kno...self-employed/