Why does silver plating require undercoats of copper and nickel? I came across a question that was about silver plating (of steel), but I couldn't help but wonder why the sequence was illustrated as this:

step 1 A coating of copper is applied to the object. 

step 2 A coating of nickel is applied to the object. 

step 3 The coating of silver is applied to the object.

Why are these initial coats of copper and nickel required, and why this seemingly random sequence (since nickel is in between but has the highest reactivity)?
I have read that the nickel plating helps removing oxide layers when working with stainless steel which is beneficial for the silver plating process.

Sadly I do not know why the copper is used but I suspect the context could explain the copper.