Follow these instructions that the others said, but also, when it is time to put the chicken in the hotel pans, add a bit of water or stock.  Another great thing to do is to line the bottom of the pan with some lettuce, like green leaf.  When you do this, the lettuce will wilt before the chicken, and once the chicken starts to steam, the juice from the chicken will go down into the lettuce, reconstituting it, and starting the process over again, so your chicken will...