Where would I put WaitForSeconds and the Coroutine for this to work?

Engineering isn’t so much about “where do I stick this line?” as it is about “how do I engineer this solution?”

Coroutines in a nutshell:

Splitting up larger tasks in coroutines:

Coroutines are NOT always an appropriate solution: know when to use them!

Our very own Bunny83 has also provided a Coroutine Crash Course:

https://answers.unity.com/questions/1749615/coroutines-ienumerator-not-working-as-expected.html?childToView=1749714#answer-1749714

And then, just for completeness, I use my CallAfterDelay class for delayed action.

See usage notes at bottom below gist code.