If you want to pass examinations, you must study grammar. However, if you want to speak English fluently, you should try to learn English without studying the grammar.
Studying grammar is an extremely complicated and time consuming method which will only slow you down and confuse you all the time. You will translate and think about the rules when creating sentences instead of naturally saying a sentence like a native speaker.
It cannot be ignored that only a small number of English speakers know 30% of all the grammar rules.
For instance, Many Indian students know more grammar than native speakers. I can confidently say this with my personal experience. I often ask my native English friends some grammar questions, and only a few of them know the correct answer.In the USA 75% English speakers do not know typical grammatical rules while speaking however, they are fluent in English and can read, speak, listen, and communicate effectively.
Do you still want to cram the grammar rules and the definition of tenses?
OR
Do you want to speak English fluently and naturally?