If you are doing fairly set hours, nailit, they should give you a letter with the number of hours you are entitled to, off paid per year. If you have started partway through their annual leave year, it will be slightly less. But will be based on the number of hours you work on average.
It used to be the average hours of 12 weeks in a row, that you got paid for the 13th week off, although I think that has changed now so that you can take annual leave at different times.