need explain the code (function, how it run)

there 3 codes in zip file. when you open it you read the file “main.c” only the other file you don’t have read or do anything.
the LAB1 exercise2 each like code it has the appendix like (// Start the delay counter at 25,000 or // Count down until the delay counter reaches 0) please doing same thing for lab1 exercise3 and exercise4.
then create three flow chart for three exercise ( I have an example how to to it you can review and try it).
to understand the function of three code you can read the lab1 instruction