Hello, 

i am making a 3-tier buttercream cake that has large S and C swirls that look as if they extend from one tier to the next. They are not piped on so I assume they are cut out from gum paste and or fondant. I have a picture but don't know how to post it. My question is how should I attach these to the cake and what should I make them out of? I wil then be piping around the edges on the swirls. Thank you!

From what you describe I suggest using fondant rolled in to thin snakes   It could be done w/gumpaste   As for posting a picture I found using my phone the best   Just click on gallery then scroll down to a bottom “post a picture “  than a drop down wants to know where they are — I have mine on the phone so just click that choice & all my pictures come up I choose the one I want & it posts   Hope it works that easily for you