Explain a Concept

Explain [concept] for a developer who knows [related technology] but is new to [this area].

I understand: [what you already know]
I'm confused about: [specific confusion]

Please explain:
1. What [concept] is and why it matters
2. How it relates to [thing I already know]
3. A simple example in code
4. Common pitfalls when learning this
5. What to learn next