If you want to learn grammar for speaking english then i just suggest you that speaking is the first step for any English learner. So if you are a novice at English, please focus on your speaking and listening skills prior to studying grammar. After being able to speak English fluently, you will realize how much easier grammar is. But it does not work the other way around. Being fluent in English speaking will help you with your grammar studies, but studying grammar will not help you with your speaking.
studying grammar can slow your progress down significantly. Basic grammar is a necessity, but focusing on grammar will prevent you from being able to speak English fluently in a reasonable time frame. Grammar is most effective to improve communication and writing skills, but this only pertains to those who have a solid foundation in English fluency.