if bootstrap doesn't work 
please go to this link: https://getbootstrap.com/docs/4.4/getting-started/introduction/
copy and paste the css and js cdn into HeadTagTemplate.php and BootstrapJS.php respectively

Introduction:
data/employees.txt : store all input data
include/ : all the repeated elements or php file that need to load/update using ajax
javascript/nav.js : all related jquery and javascript code
employeesProfile/ store the employee profile image

run.php : act as the main program file
employeeprocess.php : will contain all the necessary class

Youtube video: https://youtu.be/nGNXborC9hc