Spawn an object near the last object in a list.

public void Set1()
{
Debug.Log(“SetMode: Set1”);
PlatformOBJChild = Instantiate(PlatformOBJSel,
new Vector3(1.0f + iX,1.0f + iY,0.0f),Quaternion.identity) as Transform;
iX += Random.Range(1.0f,10.0f);
iY += Random.Range(1.0f,2.0f);
tList.Add(PlatformOBJChild);
}
public void Set2()
{
Debug.Log(“SetMode: Set2”);
PlatformOBJChild = Instantiate(PlatformOBJSel,
new Vector3(1.0f + iX, 1.0f + iY, 0.0f),Quaternion.identity) as Transform;
iX += Random.Range(1.0f,5.0f);
iY += Random.Range(1.0f,10.0f);
tList.Add(PlatformOBJChild);
}
public void Set3()
{
Debug.Log(“SetMode: Set3”);
PlatformOBJChild = Instantiate(PlatformOBJSel,
new Vector3(1.0f + iX, 1.0f + iY, 0.0f),Quaternion.identity) as Transform;
iX += Random.Range(1.0f,6.0f);
iY += Random.Range(3.0f,6.0f);
tList.Add(PlatformOBJChild);
}

public List<Transform> tList = new List<Transform>();
		
if (tList.Contains(null))
		{
			tList.Remove(null);
		}
				
		foreach (Transform c in tList)
		{
			Vector3 randXMove = new Vector3(Random.Range(-2.0f,-5.0f),0.0f,0.0f);
			c.localPosition += randXMove * Time.deltaTime;
			if (c == null)
				{
					return;
				}
		}

I want to be able to spawn in an object near the last Platform in the t.List. How would I go by as to do that?

Vector3 randXMove = new Vector3(Random.Range(-2.0f,-5.0f),0.0f,0.0f);

GameObject obj = (GameObject)Instantiate(yourPrefab, tList[tList.Count - 1].position + randXMove, Quaternion.Identity);