how could I start Lemon and papaya farms
I would like to cultivate a lemon, papaya and curry leaf farm. Please advise me.
First, let's be clear on your question. If by farm you mean growing these things as a commercial crop meant to produce a product and (hopefully) profits, you'll need to study agricultural methods in your area. Probably the best source of advice for you in this case would be from the nearest university with an agriculture department. Perhaps you should do more online research into farming before you start such a venture.
If, however, what you're asking about is gardening, that is growing plants for consumption only by your family and possibly a few friends, here are some articles to get you started.