hello monam,
it will be my pleasure if i can help you out… i am seriously not getting what you want to ask…her i am sending you two links one for LED interfacing and one for key pad interfacing
LED interfacing link check here
http://www.engineersgarage.com/microcontroller/8051projects/interface-leds-AT89C51-circuit
KEYPAD interfacing check here
http://www.engineersgarage.com/microcontroller/8051projects/interface-keypad-AT89C51-circuit
let me know where exactly you not getting… and please be clear
thank you