Hello Shantilal,
Firstly, You will have to ask you relative, who is already a farmer of very old age and have some agricultural land to give you some part of their agricultural land through will. Then you will have to get this will registered. After his death, the said land will get transferred to you legally. Otherwise you can make arrangements to purchase the agricultural land through registered will.
Secondly, You will have to get permission from collector's office mentioning your intent to engage into agricultural activity in the area.
You will also have to take the NA permission from collector and buy & used that land.
