Please give me any advice about making a 3-D Garbage Truck cake. I am a newbie and this is my first 3-D cake.

i would stack some sheet cakes up quite tall and carve it to look like the back bit of the truck (the part where they put all the garbage) and then just in front of it i would stack some smaller cakes and carve that to look like the driving part.

this is the kind of truck i'm thinking of, you might be thinking of a different type though?

Yes, this is the type. Thanks. I heard you should freeze the cakes first before carving them. Is that what you think? I actually found a pattern for cutting it.

Yes, I would definitely freeze before carving ( but let it thaw out a little ) as it will be firmer and easier to handle!