If you procure paneer from the market because of the paucity of time, then it is fine but in case you are unaware of the technique how to make it, the method listed below will help.
1. Take a heavy bottom pan and add milk to it
2. Heat the milk, enough to let it boil once.
3. Reduce the heat and add any citrus agent which accelerates the process of conversion of milk to paneer. The citrus agent may be curd, lemon or even 'taatri .
The amount of the agent will depend upon the amount of milk. For a liter of milk when taken, for example, 1/2 cup of sour yogurt or curd should be enough. In case of lemon, 1 tbsp of lime juice will suffice one liter of milk. Similarly, two teaspoons of powdered 'taatri' should be enough for 1 liter of milk.
4. After the addition of these agents, stir the milk gently. You might notice the change in color and texture of the milk.
5. Turn the flame off when the milk gets converted into a mixture of White precipitates and water on the top.
6. These white precipitates are actually 'Paneer' and sieve the mixture to get 'Paneer' separated from that mixture.
7. In order to get the 'Paneer' firmly set like dairy shops do have, gather all its crumbles so obtained and place them underneath a plate or a flat based utensil. This will help in 'Paneer' acquiring the shape of the base of the container.
Note: You may use milk which was already placed at room temperature instead of the one in the refrigerator. As the chilled milk takes long to get converted into 'Paneer'.