Chetan,
You are doing just what I did: try to get organized beforehand. There will be things you'll miss or won't use, but you will likely be glad you got ready.

Baking soda--any old kind. They usually give you a recipe in radiation, but I never made up a big batch, just a small one so I guessed (small amount for a glass of water) Some will have you put salt in it as well, but if you have sores, the salt is not good. I've seen a proportion of baking soda/salt/water on this web site before.

The fluoride trays: you want it to be in contact with the occlusal surface of the teeth, that means where they contact.
Some fluoride spreads easier than others. If you have to you can use a finger or toothbrush to spread it. You will have some squish through when you place the trays, but not so much it really bothers you. What does come through, just get rid of it with your finger or gauze or tissue. You'll get better at it. My instructions were half-way up, but for me that was too much, maybe I could not eye-ball half way good enough. Again, they surely gave you instructions on this, or they will give you.

Counting calories--to do it correctly you would have to know the caloric amount for each recipe ingredient, calculate the amount, add it together. Lots of work unless you make the same things a lot . . . If your weight is stable and you know what you usually consume, then you should be good. Trouble is, you might not be eating the same stuff throughout treatment. You should have access to a dietician at the cancer center to help you with this.
Of course if you are using a PEG then I could not speak to the procedure regarding calories. For myself I am sure I did not consume 2500 calories, I am kinda small. I don't know how much I did eat, just that my weight was fairly stable, which is what's important.

Home cooked Indian food does sound delicious to me!
Anne