Start by keeping the milk and curd ready. Boil the milk in medium low flame for 5 minutes. Stir it occasionally.

When it's about to boil (Don't let it boil), add curd, lemon juice and salt. Stir it gently. The mixture will start to curdle.

Continue stirring gently until it completely curdles.

Set the colander/strainer in a large bowl. Place a cheese cloth or muslin cloth over it. Pour the curdled mixture to it gently.

After transferring the entire curdled mixture, gather the corners of the cloth and tie it up. Let it stand for 30 minutes at least or until the water is completely drained off. Squeeze out the cheese cloth occasionally to drain off the water. Once the water is completely drained off , open the cloth. The ricotta cheese is ready for use!  The whey(drained water) can be used to knead roti dough, making bread, pancakes etc,