how to do understand the future and past tense in French

Ppour retenir et comprendre le futur tu penses à demain, exemple : demain j'irai à la piscine.et pour le passé pense à "hier"exemple : hier j'ai été à la piscine.(How to do Understand the future and past tense in French to hold the future you think about tomorrow example: Tomorrow I will go to the pool the past and think of "yesterday" example: yesterday I was at the pool)