How do you use the OnRectTransformDimensionsChange function?

I wanted a collision detector that goes around my camera view/boarder so if an object $$anonymous$$ts the edge of a screen the object bounces back.

I've stumbled upon t$$anonymous$$s and t$$anonymous$$s, but a bit lost on actually how to use it. Since I don't quite get the code bit for the second link specially.

Would there be anyone help me out understand that code bit a bit better and help me solve t$$anonymous$$s problem?