Demand/Supply estimate model help, please!

hi, i'm attempting to create a demand estimate and supply model to measure HR data for class. The end reuslt to be able to predict exit/incoming rates. Data I have includes list of employees at different monthes, those fired in a given month, and the numbers of all those interviewed and eventually hired.
I'm a little confused about how to create a demand estimate model? would a regression model be better suited and if so how would i go about that?

Thank you so much! any help is appreciated