Go to this site: lektorek.org/lektorek/
Click on "Polish Reference Grammar", and you will download by far the best grammar of the Polish language that is available in English. It will answer practically all of your grammar questions.
From the same page, you can also click on "First year Polish course", and then on "Lessons" on the page it takes you to. That is by far the best textbook for leaning Polish for English speakers.
And it's free, courtesy of the author.
Polish has chiefly only one extant "past tense" (czas przeszly), "byc" < "byl(a)", "bylismy", "miec" < "mial(em/am)" etc.., the past participle being formed by adding any one of a number of such endings.
What Polish though lacks in terms of tenses compared with English or French, she more than compensates for in a wealth of "verbal aspects", far too complex a subject to summarize right here and now.