I tend to pull the knife, but then there are two ways to do that! I know some people who twist the whole hand at the wrist to provide the movement in the blade. I prefer to use the muscles in my hand and squeeze my hand closed, pulling the knife through the wood as it goes.
As Duncan says, get one that you pull to start with and see what happens when you attack the wood, it will be instinct I think
If you then decide that it feels all too unnatural try one that requires yo to push instead and see if that helps.
best thing to do is to try a few different knives and see what you like :0 Mine are very different to Duncan's, but they both work if you know how to use them