Which political party is tasked with forming the government?

Okay, so after a general election, the process of forming a government begins. It's not as simple as just the most popular party automatically taking charge. The key thing to remember is that the UK operates under a parliamentary system. This means that people vote for a Member of Parliament, or MP, to represent their local area in the House of Commons. The political party that wins the *majority* of these seats – meaning more than half of all the MPs – is the one that gets to form the government. The leader of that party then usually becomes the Prime Minister. While the party with the most votes often *does* win the most seats, it's the number of MPs they have that matters, not the raw vote count. The Queen plays a largely ceremonial role these days, and doesn't appoint the government. So, it's all about that majority in Parliament!
Imagine Parliament as a classroom, the party with the most 'students' gets to rule as they can make up 'majority' rules.