So I am making a chocolate ganache cake for the first time and I have a question: Do I need to cover the cake with buttercream before pouring the ganache over it? Or goes the ganache just go right on top of the 'naked' cake? Thanks

I let my ganache get to room temp and spread it on like buttercream.. You don't need to put BC on under tha ganache.. you can skim coat it with some ganache and them pour it.. but your best bet for a nice smooth finish with sharp edges is to crumb coat it with some room temp ganache and them wram it up and pour it over the cake.

I let my ganache cool to about room temperature then use a very thin layer to crumb coat my cake. Allow the cake to set a little while then spoon the slightly thickened ganache onto the top and over the sides of the cake. I find it very easy to spread the ganache over the entire cake to get a nice pretty covering. You can get it slick or leave it wavy. I'm fairly new to the ganache world, but sure love working with it. I make most mine with semi sweet choc chips.

well since there's two replies in agreement with each other, then that's what I'll do. Thanks for the good advice, ladies!