Referencing gives you a chance to show off the breadth and depth of your reading. It gives due credit to others in your field, as their work was obviously significant enough for you to include in your own work. Referencing accurately shows off your academic integrity skills and ensures you don't get caught out for plagiarising someone else's ideas. The University of Cambridge has a detailed and useful website dedicated to Plagiarism and Academic Misconduct if you want to read more about this topic.
A good starting point for referencing is Cite Them Right Online
Stylistic conventions vary between subjects. You should consult your Course Director, Supervisor or Lecturer if you are unsure which are used in your Faculty or Department. Most lecturers also issue written guidance on the relevant scholarly conventions and you should read and follow this advice
Referencing is definitely a process that takes time to get right but thankfully there are tools, called reference managers, available that can help take a lot of the pressure off.
If you need further advice or help with getting a reference manager set up, you can book a referencing 1-2-1 consultation with a member of the Biological Sciences libraries team.
It depends as the rules around who owns something and who else can use it can vary hugely. For more information on copyright, have a look at our dedicated Copyright for Researchers guide which has lots of information and contact details for further help.