I can´t believe you are having a hard time understanding verbs! The English verb tenses are so easy! Why do you need to understand them? Just use them! I´m an Argentinian teacher of English and when someone asks me how to use the "Pretérito Pluscuamperfecto" or the "Futuro Imperfecto" in Spanish, I just don´t know. I just use them! You are really very lucky to have such simple verb tenses! So just enjoy it!