Line a fine mesh strainer with muslin cloth/malmal. Keep the strainer on a deep bowl which will be used to collect the whey.
Once the liquid whey has drained, you will be left with creamy hung curd. Just whisk it and use in the recipe as required. Store hung curd in the fridge.
Hung Curd is similar to Greek yogurt, and can be used in recipes which call for Greek yogurt. It should be made using fresh dahi yogurt and not packaged.