I test timers. Some arrive defective.
GE makes a good timer, and sometimes the instructions are hard to understand.
1) When I have a problem with timer instructions, which is frequently, I write out the instructions which seems to help me understand.
2) Sometimes you need to reset the timer and then it recovers and works fine afterward.
Open link below to identify timer and download manual.
I am looking at the manual, and can see it has illustrations that show how the display should appear at each step.
1) The manual is too long for space allowed free answers, so I can't write out the instructions.
2) However, I suggest you reset the timer and then go through instructions carefully.
3) When you reach a specific point in manual that is confusing, simply add a comment to this post and I'll answer.
Add a comment for more free help.
Also take advantage of fixya phone service.
For a price, expert speaks with you over phone while you work on timer or any do-it-yourself project.
Fixya is always less expensive than a service call.