Can anyone offer advice on applying fondant deco to buttercream iced cake? I am going to make a race car themed cake that will need black fondant checkers applied to one 10 in round. This will be my first time working with fondant and I need some tips like how can to make the checkers stick and what temp is best to apply the fondant. Thanks!

If your BC hasn't crusted yet, you should be able to put them on right after you've iced the cake. They'll stick just fine by themselves.

I've used a small amount of piping gel when the buttercream has crusted. That should work fine for the checks. For heavier items such as drapes and bows I usually use melted chocolate. Either way, just hold it in place for a few seconds and if using a turntable, turn slowly! Hope that helps.