Treat it as an example of how to approach it and then make your own, rather than use it as a plug & play solutuon that suits all cases. In order to use and adapt it to your needs, you’d need to fully understand how it works anyway.
Here, it seems that calling SetHAS assigns new values to Health, Armor and Shield repectively. It would be up to you to have and calculate those vars separately.
A 6 year older me would do things slightly differently, rely more on materials.