Kneading the Chhana is very important for the Boiled/Steamed Bengali Sweets, so I went ahead and followed the same for the Sandesh Versions as well. I have recorded the detailed steps I have followed while kneading the chhana, hope it is useful
Once you make the soft chhana for the Bengali Sweets, the tied fresh chhana can be left to be hung for about 30 mins. If you are not going to use it right away, I suggest you refrigerate the chhana in an airtight container until using. This fresh cheese will be fresh for a couple of days. When you are about to use it again, bring to room temperature, knead it really well for the chhana to come down to normal temperature and then proceed to make the sweets.
These steps are very important when you are making boiled Bengali Sweets such as Ragolla, Ras Malai Etc. Since I am making 26 different Bengali Sweets with Chhana, I thought I might as well do this from scratch.
Tips, Tricks to Knead Chhana for Soft Bengali Sweets.
- Remove the chhana from the cloth, take a wide plate that you can hold well. Crumble the paneer. The following steps can also be done on a kitchen counter, I preferred a wide plate
- Once you crumble the paneer/chhana, using your palm heel, press it well down away from you. Gather back the paneer, again roll forward, using pressure on your palm heel.
- Each time you knead with force going forward, gather all the cheese back and make a ball.
- This kneading forward and gathering of cheese can go for about 15 mins.
- By now the cheese granules are really broken down and the granules look very tiny.
- To check if the chhana is really kneaded well, press the cheese forward, if you notice the grains are big, you will have to knead again.
- Knead forward and backward for another 10 mins and you are done.
- To know if the chhana is kneaded enough and will result in a soft melt in the mouth Raragullas, pinch out a small ball, and roll between your palms.
- If you notice the ball is formed without any cracks or breaking, it means you have kneaded it enough.
Another thing you will observe is the cheese fat glistening on your palms. You can also smell that slightly sweetish aroma of the fresh chhana.
This kneaded paneer/chhana can then be used to make Kancha golla, Norom Paak or any of the boiled/steamed Sweets.
Step by Step Pictures for Kneading the chhana to a soft texture:
Remove the chhana from the cloth, take a wide plate that you can hold well. Crumble the paneer. 
Once you crumble the paneer/chhana, using your palm heal, press it well down away from you. 
Gather back the paneer, again roll forward, using pressure on your palm heel.
Each time you knead with force going forward, gather all the cheese back and make a ball.
This kneading forward and gathering of cheese can go for about 15 mins.
By now the cheese granules are really broken down and the granules look very tiny.
To check if the chhana is really kneaded well, press the cheese forward, if you notice the grains are big, you will have to knead again.
Knead forward and backward for another 10 mins and you are done.
In the above picture, the ball on the left is soft and well kneaded chhana, the right is still not done. See the difference in the texture.
To know if the chhana is kneaded enough and will result in a soft melt in the mouth Rasagullas, pinch out a small ball, and roll between your palms.
If you notice the ball is formed without any cracks or breaking, it means you have kneaded it enough.
This kneaded paneer/chhana can then be used to make Kancha golla, Norom Paak or any of the boiled/steamed Sweets.
