This document is a guide to help students prepare for Paper 2 of their GCSE exam on medicine through time, which will involve answering questions using sources. It introduces the 5 main types of questions that may be asked: comprehension, comprehension in context, reliability/usefulness/value of sources, source comparison, and interpretation. The guide aims to help students develop the skills needed to perform well on the exam by explaining how examiners want questions answered and including sample questions with worked through answers.