Cheers表示“谢谢”的用法

"Hi, this is Lucy, a student from Hong Kong. I was in the UK for an exchange programme. May I ask a question about the way people say 'thank you'? I usually hear people say 'cheers' instead of 'thank you' or 'thanks'. Are there any differences between 'cheers' and 'thanks'? Is 'cheers' less formal? And when do we use 'cheers' and when do we use 'thanks'? I am confused. Thank you very much!"