To attend the indoor areas of the Welcome Fair you will need to get a ticket for each area of the event.
The tickets provide an an entry time, and you can enter the area at any time during the time slot on your ticket, so if you have an 11am-12pm entry ticket you can enter the selected space at any time in this time period.
You do not need a ticket to visit the outdoor areas of the Fair in Graduate Square and Atlee Square.