Can someone explain the crumb coat to me. Do you do this once the cake is cooled. I am just confused.
You crumb coat the cake after you have trimmed it and filled it with your filling. You ice the cake with a thin layer of icing, just enough to trap the crumbs. You let it sit and crust, maybe 15 minutes. Then you can frost your cake with you final layer of frosting without having to worry about crumbs showing through.
Icing and filling never touch the cake until it is completely cooled or they will melt.
After the cake is out of the oven for about 10 minutes, turn it out of the pan on a cake rack; let cool another 10-15 minutes then cover w/either the cake pan or plastic. Let cool another 1 hr or so until it is no longer warm to the touch. Now you can fill and crumb coat as lindambc said.