You will get your timetable during O-week (1-3 March). You can get it from the Student Centre in the Carslaw Building (but there is usually a long line), or you can get it from Student Adminstration i your Myuni account.
You can't make your own timetable. The uni will provide you with a timetable, but you can rearrange it to a certain extent, depending on the amount of streams there are for lectures/tutorials/labs. If there is only one stream available, you will have to attend that particular stream and can't rearrange it.