Self-Stopping 99-0 Countdown Clock

I am using multisim trying to make a self stopping down counter from 99-0. the only requirements are below! I've tried a few different ways and I have no idea. Please help!!

· Build a 2-digit countdown clock using two 7-segment displays with the following characteristics:

Is this a homework assignment?

No, it is for work, my boss asked today for me to have it done by tonight

hi,
This link should give you a good starting point.
https://www.electro-tech-online.com/blog-entries/basic-3-digit-led-decade-up-down-counter1.123/

E