Here's a summary guide on the roles and responsibilities on the actual day
Roles and responsibilities for wedding day
Brothers
Fetch the bride
Bridal car driver
Driver for sisters
Liaise with photographer / videographer
ROM and Pre-banquet
Take charge of stuff to bring for ROM and banquet / loading to bridal car
Driver for family / relatives to ROM venue
Coordinate and ensure program schedule / prompting
Liaise with banquet manager / monitor wine and beer consumption
Liaise with JP / give ang pao
Usher in guests for banquet / ROM
Receptionists
Guard Ang Pao box and deliver gifts to safe
Banquet
Coordinate playing of photo montages / slideshows / march in music, take care of laptop
Yam Seng party
Arrange guest and clear path for photo taking
Sisters
Fetch the bride
To accompany and assist bride
ROM and Pre-banquet
Receptionists