The three threads of the story
The three threads of the story

This topic makes most sense as three linked stories at once: British imperial power, Congress-led nationalism, and Muslim political separatism. India mattered enormously to Britain for soldiers, taxes, markets, raw materials and imperial prestige.
Step-by-step lessons on Edexcel A Level History India, c1914–48: the road to independence. Each one builds up to exam-style questions. Build a secure grasp of the outline narrative for your breadth and depth periods first, since the source-evaluation and historical-interpretations questions that carry a large share of the marks depend on that contextual knowledge.