get (one's) feet on the ground
To become comfortable with a particular situation. I know you're nervous right now, but I'm sure you'll feel better once you get your feet on the ground in your new position.
get your feet on the ground
mainly AMERICANIf you get your feet on the ground, you become used to a situation and confident in it. It takes a while to get your feet on the ground when you start a new job. We are the new boys and we have it all to do. We need to get our feet on the ground first. Compare with have your feet on the ground. Compare with keep your feet on the ground.