Ride-on problem

I just bought a new John Deere Ride on mower (24 hp) and I can't get
it started. I attached the battery cables (light turns on okay),
checked the charge (greater than 80%), pushed in the rod at the back,
pushed the park brake up into locked position (I'm assuming it's just
moving that round lever up to engage the park brake...the directions
aren't clear on that), push up the throttle and choke to max, made
sure the yellow engagement button was down, added a gallon of fresh
gas and checked the oil then turned the key.

And nothing.

Any idea what I'm doing wrong? (Can't get anyone at Home Depot today
who knows how to operate one....grrr).

Thanks!