Пизда, как граматику то выучить
English grammar is the easiest part of English language. It's easier than almost any other language's grammar. Maybe only Japanese's grammar is easier from the languages I've learned.
Some of the tenses you need so seldom that they are even worth remembering. Like the past perfect tense, when the action was completed at some point in the past before something else happened.
If you need English just for reading and talking, and not for an exam, you can just leave dat bullshit and u can use past simple.
Americans don't use the grammar much anyway.
They talk like they are too busy with a dick in their mouth. So, just practice more and some patterns will get stuck in your head.