How to make count down timer from 9-0 display 7 segment

Hai anybody can help me?

i need some advise how to make count down timer from 9-0 with push button, when push the button1 start the timer and push the button2 to stop and reset.
with single 7 segment display.

here my pin int A = 2;
int B = 3;
int C = 4;
int D = 6;
int DP = 5;
int E = 7;
int F = 8;
int G = 9;

int switchUpPin = 13;
int switchDownPin = 12;

Do you know how to display a single non changing number on the display ?

Please see Read this before posting a programming question and follow the advice given about posting code and error messages

If you don’t have much experience in Arduino, then you can have a look at libraries which can help you :

UKHeliBob:
Do you know how to display a single non changing number on the display ?

Please see Read this before posting a programming question and follow the advice given about posting code and error messages

sorry, im forgot .. thank you for the advise