As the fine people above me have stated, yes you must use the Master Timetable.
I preferred Google Calendar to Excel and I had 2 Google accounts so I drew up 1st term and 2nd term (but Google will email you notifications when it thinks you have Econ 1B03
)
I liked Google because you can drag and drop and mess around with your "events" (classes) without the pain of deleting them and retyping everything.
However, after jumping on the Mac bandwagon, I now recommend iCal.
It just feels much more efficient to me and I like the possibility of drawing up different Calendars in different colours