I answer questions for free, and will assist you.
Free assistance is not the same as paid phone service because I cannot speak to you live to tell exactly where you are having trouble.
However I test these timers and am in a position to assist you.
You did not say which timer you are trying to program.
You posted under ST01C Intermatic timer, but many folks post under this timer but have a different timer which requires different programming steps.
If you want free assistance, then add a comment at any time.
Here are 2 links that will help us get started:
Programming dawn-dusk timers takes more steps than I can write out here, and the steps also take illustrations.
Links above shows illustrations and simplified programming steps.
So here's what I can do for you free of charge:
First, I want you to open links above to identify your timer.
Then you go through the steps as far as possible.
At any time, add a comment and say exactly where you are.
I will respond with ASSISTance for all trouble spots until your timer is working.