It looks like you've just finished step 3. Instead of running a function, you just print out a statement. A function is defined in the following way:
def addstudent():
print("Student Added.")
then called by writing addstudent().
I would recommend using a while loop for your input. You can define the menu option outside the loop, put the print statement inside the loop, and do while(#valid option is not picked), then put the if statements after the while. Or you can do a while loop and continue the loop if a valid option is not selected.
Additionally, a dictionary is defined in the following way:
my_dict = {key:definition,...}
