Hi Tan,

Since you said you are starting new, multiplexing is not the most easy topic to comprehend.

If I were you, the first step would be to just manage to display the numerals 0-9 on a single display. And for this the circuit posted by Charles is fine. Just ignore the following :

*The battery back up
*Relay connections to P3.7
*All four push buttons and thus the connection to p3.4
*The transistor drives from p3.1 to p3.3 and corresponding displays.

With what remains you can write a small code to display 0-9 with an interval, of say, 1 sec between each digit and that which rolls over continuosly after reset. Unless you can do this your self any amount of search is going to be futile.

Raghu