@MukundChaskar Your question says, "Tell me "How do you conjugate the verb to speak in Present, Past and Future tense, give me some examples too." how do you say in Japanese? That's why I answered by writing the translation of that.
Any way, I can tell you how to learn the verb conjugation here. It will talke a lot of time. Please be patient.
I'll show you a sample. 勉強する present 勉強した past 勉強するだろう future
はたらく present はたらいた past はたらくだろう future
You have to mmemorize all conjugations one by one. Everybody learning foreign language does this.