Freelance/Employment contracts (Bristol)

Hey! I am new to the UK, and would have the opportunity to do a web design job for a company, however I have no idea about how I cold work and pay taxes, as the company is not looking to hire on a permanent basis. I applied for the National Insurance number so I will have that by January.
I was thinking about doing this job as a freelancer, however I don't really know what that implies.
Is there an option in which the company could pay the taxes for me?
If freelancing is the best options, could you please tell me which would be the necessary steps to take in order to fulfil the legal requirements?