First take the bel fruits and with a rolling pin (belan) hit all around.

You will see the outer hard shell cracking. Open the hard shell and you will see a brown colored pulp.

With a spoon scoop out the soft pulp.
Add the scooped soft pulp in a bowl.

Then add 1 cup chilled water.
Soak this mixture for 20 minutes.
After 20 minutes, with a veggie masher, mash the pulp. Mash very well.

Then using a strainer, strain the mashed mixture in parts. Also overall add about ½ to ¾ cup chilled water while straining.
With a spoon stir so that the mixture is strained well.

Once the mixture is strained, then add 12 tablespoons of sugar and water can be adjusted as per your requirements.
Then add chat masala powder, and 2 pinches of black salt.