Carbing up?

[Bigguyfitness]

Hello,
I'm currently following Kris Gethin's 12 week video trainer. I had someone who used to be a competitive bodybuilder once say that they "carbed up" before competitions. I assume that right before you compete you eat a lot of carbs. My questions are as follows:

1.)When do you injest them?

2.)How much?

3.)What kinds?

Any and all help would be apreciated with this. I'm having some professional photos done at the very end of this (last day is Dec 29th) and I want to look the best I can.

Thanks!