Panasonic nn c784mf

I have a Panasonic Oven model No NN-C784MF/Wf in instruction manual they had said we need to operate the oven in convection mode without food for 20 minutes when using the convection bake for the first time. And this will eliminate the oil which which for rust protection. My doubt is that do we need to keep the glass tray and the roller ring Which comes along with the oven when we purchase) inside the oven when we do this process