# Start()

> Starts an instance of a subsystem. Once the instance is started, the subsystem representing this instance is active and can be interacted with.

## Definition

* **Type:** Method
* **Namespace:** [UnityEngine.SubsystemsImplementation](/engine/6000.5/script-reference/unityengine/subsystemsimplementation.md)
* **Assembly:** UnityEngine.SubsystemsModule

```csharp
public void Start()
```