Hello guys iam a Dentist but have been into electronics as a hobby from the last 12 years

well i am not that good in coding (microcontrollers) so i need help from you Guys and the Admin as i couldnt find any thing on the net

I am building a Dual 7 - segment 20 and 40 seconds countdown timer for the dental composite curing light. here are the features that i needed

1. Dual 7- segment display
2. Countdown timer with 20 and 40 seconds delays
3. Timer should turn on \ off with the same button
4. Two different buttons for 20secs and 40 secs
5. Display should start at 20 then end at 0 same goes for 40 secs
6. Small beep when a button is pressed then after the countdown has elapsed a long beep should be heard
7. one output should go high when the timer statrs and should go low when the countdown ends ( this will drive a 5w blue led)
8. when the switch is pressed while countdown the timer should turnoff
9. when the timer is not running it should go in to sleepmode and blink an LED every 10 secs

Guys i have written a code for the above project but could only achieve the
following

1. switch is pressed then 5w led turns on and after 20secs turns off ( same goes for 40 secs)
2. beeper sounds when a button is pressed and then produces a long beep after the countdown is over

so i need help from the big brains out there to help me finish the project