In Unity, you can get a child GameObject by using the “Transform” component which has functionality associated with GameObject hierarchy. Every GameObject in Unity has a Transform component attached to it and this can be used to control the object’s position, rotation, and scale in the 3D space.

If you want to get a reference to a child GameObject, you have to use the “Transform” component’s ‘Find’ method, or ‘GetChild’ method.

Here’s an example code snippet of how to use the ‘Find’ method:

“`csharp
Transform childTransform = parentGameObject.transform.Find(“ChildGameObjectName”);
GameObject childGameObject = childTransform.gameObject;
“`

In the above code, “parentGameObject” should be replaced with the GameObject that has the child you want to get, and “ChildGameObjectName” is the name of the child GameObject you’re trying to retrieve. This method will return the Transform of the child GameObject. From that, you would then get the GameObject itself.

On the other hand, if you want to get a child GameObject without searching by its name, you can use the ‘GetChild’ method. It retrieves a child by its index in the hierarchy of the parent GameObject. Here is an example:

“`csharp
Transform childTransform = parentGameObject.transform.GetChild(index);
GameObject childGameObject = childTransform.gameObject;
“`

In this case, replace “index” with the index of the child GameObject you want to get. This can be quite useful especially when you’re dealing with a lot of child objects and don’t want to hard-code their names.

Remember that in Unity, the hierarchy is zero-indexed so the first child GameObject of a parent would be at index 0.