I am not enrolled in a class through WINS yet (but will be soon), but I still need to be able to get to the material in D2L in order to keep up with the class. How I can access the course materials in D2L?

Unfortunately, we cannot add individuals to a course outside of WINS. The classlists (list of students enrolled in a course) are updated nightly by the WINS system. So, normally, students are to be able to access the courses the morning following their enrollment in WINS. Until then, see if your instructor can provide you with the course materials.