Help for Digital Pet Coding

I found a cirtual pet for arduino uno&nokia 5110. I'm re-moding this. I've added a few meals, made a few changes. But now I want to add sleep.
1st Question
Sleep, for example, will be evaluated over 100. If sleep>90 The screen will flash every 5 seconds. How could I do that?
2nd Question
"If hungry=0, Count from 10 to 0. If she's still hungry when she's 0,"
How could I Do that? Thanks for helps!! Healthy days!!

I can't suggest code-modifications for a code that I can't see