Given that this is a hypothetical scenario, first you need to identify the issues that you will face.
1. India has massive air power and to an extent also similar artillery capability. That's how the attack will begin. India will bomb our air bases and take out our airforce within hours. Even if we manage to put some planes on the sky (considering the current fleet), it wont pose much of a threat. So BAF will be history very soon.
2. Although we have a capable Navy, India probably edge ahead in numerical advantage. I doubt there will be head-to-head naval battle but India can certainly enforce a blockade and we will probably hold some water near to our shores. However, the major issue that our Navy will face is aerial attacks by IAF after they have taken out our joke of an airforce. But I think the Navy will be able to put up a fight.
3. This will dry up our supplies, unless we keep a road open through Myanmar to China. However, I doubt that will happen as Myanmar is an ally for India.
There's only much IAF and IN can do but to win a war, India has to send boots on the ground. And it will be nearly impossible to beat us on the ground.
We have a very decent and well-equipped army numbering around 300,000 (Dont read the 200,000 nonsense, they are old figures). Add to it, some 70k-80k BGB and of course, 6 million Ansars & VDPs who in times of war fall under the command of the Army. Supplies would not be an issue as we have local production and make guns, bullets, grenades, mortar and even RPGs (correct me if there are more). Plus, our terrain remains our best advantage. IA will never be able to win a war on the ground.
Here, I am not even counting our special divisions like PGR, Para-Commandoes and SWADS.
I can tell you that our military ALWAYS trains keeping India in mind. I have heard this millions of times from Army members who dont hesitate to disclose it. Its just the reality. So our military is very well aware of what India will bring up and what are we going to do about it.
But of course, the above scenario is hypothetical so I would not worry about it too much!