I have made a new board. I want to add it to the arduino IDE and program it. How can i do it? I don't want to modify the board.txt file.
KaustubhAgarwal: I don't want to modify the board.txt file.
Why not? Just make a backup copy of it first.
However I will be very interested if some can write a walk-through of the process (or post a link to one).
To answer this info about the board is needed.
Bootloader or ISP?
Etc, etc, etc.
The short answer is that it is possible to create board repository that references an Arduino core (or the standard). You should not modify the Arduino core for a new board. At least not for release.
If you add a package information file the board can be installed with the Boards Manager in the Arduino IDE.