HOW CAN I GET MY TIMER TO WORK PROPERLY, CANNON TRADITIONAL 1000 GAS 10755G?

I AM STILL TRYING TO GET THE TIMER TO WORK PROPERLY. I AM DOING IT USING THE MANUAL BIT BY BIT, SETTING THE COOK TIME, WAITING FOR IT TO GO BACK TO THE TIME AND THEN SETTING THE END TIME. WHEN I'VE DONE THIS IT JUST STARTS TO BEEP AND IF I TURN THE GAS ON THE MARK TO COOK, IT COMES ON IMMEDIATELY INSTEAD OF WAITING FOR THE TIMER TO KICK IN AND TURN ON WHEN IT DOES, CONTINUOUSLY BEEPING. THE TIMER HAS WORKED PREVIOUSLY, I HAVE USED IT SUCCESSFULLY SO CAN'T BE DOING IT THAT WRONG AND TO BE HONEST IT'S NOT ROCKET SCIENCE TO SET!! I HAVEN'T HAD THE COOKER LONG. ANY HELP? DEBS