Ok, I'm a bit out of practice, so if I'm incorrect in my information, it would be helpful if someone corrected me here.
It looks like you need to add a new node onto the linked list with the student name, the university, and the id. That is what you will need to pass to the fuction of the linked list class.
void add(string student, sting university, int id){
...
}
Once you have the information passed to the function, create the node, add the information into the node, point the previous nodes next pointer to the new node, and point the current node's point to EOF, null, or whatever.
Edit:
What does your .h file look like for this class?