If there is funding available for you, the number of courses you can register may be limited by your doctoral program. Please contact your program coordinator to find out how many course days you are entitled to book, before you register online. If you want to exceed the designated number of course days, you can ask your program for further financing or pay the fee yourself.
If there is no funding available for you, you may also register for courses, but you will have to pay the course fee yourself. There is no limit to the number of courses you may register for.