And you expect us to guess how this relates to your project? Please collect information properly, and show the actual lines of code and messages together, ensuring that you identify which line of code is marked with which error.
You could also look more closely at these messages and work out for yourself:
why the identifier 'CFIS_Main' is not recognised.
why you are using the variable 'MyInstFrm', when it has not been defined in the current compilation unit.
why the call to 'MyProjectName::For_Student_Details::GetForm()' has the wrong number of arguments.