Placing meshes

Hi everyone, first day playing with CORE and I have a basic interface question. I apologize if this is simple but could not find the setting to change.

I am trying to place an object on top of my pickup truck and the object seems to move in 'steps' not smoothly. This setting prevents me from placing the object directly on the roof of the truck as there is no position 'step' on the roof. one in the truck and one over it.

How do I change this position setting to be smooth vs stepped.

Thanks everyone!