# Understand It (/docs/tracks/explainer) The largest track, and the one to read first if the vocabulary is new. These pages explain **what a thing is and why it works that way**. No task to complete, no endpoint to call. The thesis: price, route, execute, settle, prove. Read this first. Seven nouns that describe everything Ductor does, and how each maps onto the API. The execution and routing engines — coordinator, DAG model, queue, idempotency. How the Go engine is built: layers, single-writer coordinator, storage, extension points. ## A suggested order [#a-suggested-order] The primitives give you the nouns; the concepts give you the machinery that moves them; the architecture explains why the machinery is shaped that way. Steps, edges, scatter/gather, waits — the vocabulary for describing durable work. How an incoming event becomes a concrete assignment, stage by stage. What is actually guaranteed under retries and crashes — and where the gap is. Serial state ownership, parallel execution, and the boundary between them. ## Then pick a direction [#then-pick-a-direction] Once the model makes sense, the other tracks are about *doing* something with it — [clicking](/docs/tracks/nocode), [calling](/docs/tracks/api), [extending](/docs/tracks/code), or [running](/docs/tracks/operate) it.