That is a much better question! I would recommend you start with a free program like Sketchup it can create 3D components that can be imported into Vcarve,
I am still working on how to design nice 3D shapes myself and unfortunately just like being able to draw nice 2D pictures it takes some artistic skill (which I am sorely lacking). What I have been doing is taking a 2D image and then extruding it upwards to get a blocky basic 3D shape. Then comes the artistic part, you need to start smoothing edges, using the 3D form modifiers to push and pull the shape (like you would modeling clay) to get something that seems right. Sometimes you can just take the blocky 3D shape and apply a curved surface to the top and it will look fine, other times you need to tweak it for hours.
There are hundreds of hours of tutorials on youtube showing how to do this in Sketchup and Fusion360.
The easiest way for me is to just search ebay for STL files and buy completed 3D files that someone else (with more talent than me) has created. You can find people selling sets of files for pretty reasonable prices (a few dollars each)