THe VRD is a great day and a lot of fun. Actually you don't need to know any of the specifics beforehand because it won't help anyway. The best you can do to prepare is...
1. Give yourself loads of time to get there so you're relaxed when you arrive.
2. Wear business attire so you feel comfortable when you see the other candidates turning up in suits.
3.Know why you want to be cabin crew and why this airline in particular
4. Review your past work history so you can answer detailed questions about it.
5. Bring some cash to buy a coffee and snack during the breaks.
Lots of people feel they could have done better in some sections but progress anyway. It's not about being perfect. It's about being relaxed and natural and doing the best you can.
And my final tip. If you don't progress don't take it as a reflection on your ability to do the job. Realise that each airline has their own culture and are looking for different types of personality. If you don't fit one airline you may be perfect for another. So take the experience and apply to the next one.
Good luck.