can someone tell me what i should do??
when i connect board to the pc it shows status of on and led of pin 13 is on permanently
Nothing you said indicates a problem so go ahead and start having fun with your Arduino! I suggest trying out some of the sketches at File > Examples to get started learning.
That is, after installing the IDE, of course 
Usually, the led on pin13 should be blinking at a rate of 0.5 Hz (1 second on, 1 second off) . Try to cpmpile and upload the blink example and check if it works.