Immediately you can see the entire milk begins to curdle, switch off the flame.
Allow it to settle for few minutes.
Pour it in a thin cheese cloth/muslin cloth.
Rinse it under running water to remove the smell of the lemon juice.
Drain the water completely as shown in the above image.
Than tie it tightly and hang it for few hours.As shown in below image.
After the above step, take it down and put it under some weight so that it will remove the extra water from it .Let it sit for a hour and than take it out from the cloth and you can cut it into a small pieces.