# 1. Scene setup

Add the **TyrSDKPlugin** prefab to your scene (ideally once to your initial or bootstrap scene) from:

```
Packages/com.tyrads.unity-sdk/Runtime/Prefabs/TyrSDKPlugin.prefab
```

This enables API access via `TyrSDKPlugin.Instance` in code.

### Event System Requirement

The SDK UI is built using Unity’s standard Event System (UGUI). All interactive elements (buttons, toggles, input fields, etc.) rely on an active EventSystem in the scene to function correctly.

Unity UI input is processed through the EventSystem and an associated input module (e.g. StandaloneInputModule or InputSystemUIInputModule). If no EventSystem is present, UI elements will not receive input events, which may appear as if the UI is frozen or unresponsive. 

#### When you need to take action

If your project:

* Uses a custom input system, or
* Does not include a default EventSystem in the scene,

you must ensure that an EventSystem is available when the SDK UI is active. 

#### How to fix

Add an EventSystem GameObject to the scene where the SDK prefab is used.

Steps:

1. Create a new GameObject
2. Add component: EventSystem
3. Add one of the input modules:
   * StandaloneInputModule (old input system)
   * InputSystemUIInputModule (new input system)

#### Important Notes

* Unity supports only one active EventSystem per scene
* Multiple EventSystem instances may cause undefined behavior or input issues
* The SDK does not automatically include an EventSystem to avoid conflicts with existing project setups


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