i would like to burn a sketch in another arduino, using another arduino.
The 'Arduino as ISP' sketch enables one Arduino to program another via its ICSP header. In the normal case, the Arduino that is acting as the programmer would receive the program from the PC via the USB interface. If you wanted to obtain the program from a different source, you'd need to modify it to achieve that. I seem to remember that Nick Gammon published a sketch that took the program from an attached SD card, and other people have received it over a network interface.