Hey MrsOpie,
I shoot video almost exclusively for Indian weddings, Muslim, Hindu & Sikh.
You will be shooting like a documentary photographer. Finger always on the trigger. White dress sounds like either a christian wedding, or they have done the tradition religious wedding already.
Which religious background is it? Looking at the timings, it's likely a muslim or christian.
Muslim ceremony is the Nikkah. Nothing difficult here. It's just an iman say vows and prayers. The bride normally goes first in one location and then the groom goes later. Check to see if you are the only photographer. Often the groom hires his own and the bride her own. Look out for the signing of the religous papers.
Ask if there are going to be any indian tradition ceremonies. If there are, expect little things like being fed milk and sweets by close family members.
Traditionally most indian weddings seat the bride/groom on stage. Close family gather on the stage for photography. Then the guests go to the stage to get their photographs too. The Bride and Groom are normally seated. You place guests to seat beside them and others standing beside. It's quite easy, but it can be very boring if they have 300 guests and they all want the photographs taken. Whilst the B/G wont want all the group shots, the photographer is expected to take them, so as not to offend anyone.
Cake cutting is good. They normally feed one another and then immediate family feed small pieces to the B/G.
MAKE SURE your not expected to go to the bride or grooms house in between the ceremony and reception or afterward. It is often expected. Just check.
Bride leaving at the end of the reception is a major part. The bride leaves and normally cries. She says good bye to all the close family. Very important to get embraces between key family members. Embraces are long and meaningful. Plenty of emotion.
I love asian weddings. Take plenty of memory. Don't be offended if you get bossed around by guests asking you to take their photos.
Think like a photo journalist when things start to happen. I hope this helps.