how to get particular GameObject to modify

I am working an upload page where the image of different products are to be uploaded using its details , i have a gameobject with inputfields and a dropdown as the multiple upload function is done as per the multiple selection the gameobject increases to add details to perticular image ,code sample

 foreach (var simpleitem in itemlist)
            newButton = Instantiate(simplebutton) as GameObject;
            buttonscript = newButton.GetComponent<sampleitemscript>();
            buttonscript.productname2.text = simpleitem.productname;

after that game object gets increased , as much i like to upload image , **the problem is ** i need to find the first game object , here the game object is replicated so i am only getting the last inserted gameobject so any help or clue is like gods grace, <3

You could have a list that stores every instantiation and just grab the first one or you could look for it like this:

buttonscript  = ContentPanel.transform.getcomponentsinchildren<Transform>()[0].getcomponent<sampleitemscript>();

I honestly prefer the first option. creating a list and adding a simplebutton to that list when you instantiate them. It will give you more flexibility.