Help Still confused about testing SN with fish test strips

[Tulsa Sam 52]

I don't think I am the only one who is still confused about testing the potency of my rather old SN using the fish testing strips. Can anyone favor us with a simple one step at a time method without abbreviations, tell us what we need in plain English, how to do it, what kind of test strips, what we should look for on the markers, etc. How would you teach this to a 3rd grade class in school? (Not this obviously, but something you could teach.) You could even make it sticky; call it "SN Testing For Idiots".