Linked List implementation of various classes

I am relatively new to Java, and I am currently in a dead end on a program with no idea how to continue. Here is where I am at.

I implemented a typical singly linked list which contains multiple nodes of class "Student" (1 node per student). However, I need every student to be able to implement a class called "Courses" any amount of time. For example, 1 student in the linked list might have 4 courses (math, bio, phys,english) whereas another student in the linked list might have 23.

What data structure would be optimal for accessing different courses from different students? How would I tie both classes together in such a fashion?

Thanks in advance!