You can reference template variables which is passed as [`initial_context`](/core-concepts/context-and-variables#initial_context) either using the [API Trigger](/voice-agent/api-trigger) or when uploading a Sheet for a [campaign](/core-concepts/campaigns). You can also use any extracted variable as [`gathered_context`](/core-concepts/context-and-variables#gathered_context)
Dograh Voice Agents are composed of various nodes. These nodes can provide instructions to the voice agent, help you setup a [trigger](/voice-agent/api-trigger) where you can trigger the voice agent to call someone, or help you setup a [webhook](/voice-agent/webhook), where you can update the results of the call in your CRM or trigger a downstream workflow in n8n. In the next steps, we will be documenting the nodes that you can use in building the voice agent.