Nope. No real instruction can convey with clarity how to use the different past tenses in Spanish. This is just another attempt here to try and make it "clear." it is not.
Spanish fluency was a goal of mine, but really not so much any longer. Basically, because no one can really "instruct" on how to learn the language. The only way to learn it is to revert to "infancy" and just hear it spoken. So, move to a Spanish-speaking country or region and pick up what you can. Most disheartening thing I have ever attempted to do is learning Spanish.