Your Bodum vacuum coffee maker should have an "Auto" button that allows you to set automatic start times by the hour. If you cannot get the "Auto" button to work, it may be a timing issue. Bodum designed the button so that it could not be used accidentally. You need to press the "Auto" button for at least two seconds before inputting the right start time hour. Less than two seconds and the timer will not work.
There is a key difference between the present time and the start time on the coffee maker. Confusing these two can lead to problems trying to set the timer. When you first turn on your unit, it will flash a time-setting mode. This is not the timer, but the present time. You can change the present time by pressing the right-hand buttons on the coffee maker for more than two seconds to access the hours and minute options.
Storing set times occurs automatically, but this can lead to some confusion. When setting the timer by using the "Auto" button, keep in mind that not pressing any button at all for five seconds will automatically set the current time. If you pause for too long or try to switch to another function without waiting, the timer will record time improperly or not record at all. The same is true of setting the present time. Wait for several seconds to allow the unit to permanently record the problems.
If your timer will not turn on at all, your Bodum unit may be suffering from electrical problems that are keeping it from operating correctly. Bodum may guarantee your coffee maker for up to two years after you buy it, so if the timer malfunctions permanently during this time you may be able to get a replacement free of charge. Consult your manual and other Bodum materials for further information.