2014 370z automatic transmission - manual mode

ElVee

First of all, don't downshift for now. The car will absolutely downshift for you and do it just fine. Just use your normal brake and let the car do it's thing until you're more familiar with this.

Second, you can upshift any time it lets you. It'll beep when you shouldn't. And if you take too long and let the tachometer needle get into the red, a light will flash on the dash and you'll hear and feel the engine basically limit itself from going higher until you shift it. You'll eventually learn to just shift before you hit that behavior. But there's no REAL need to stay in that gear all the way up to red.

Third, when you do decide you want to downshift and the engine suddenly roars a little louder and the tachometer needle jumps up, that is completely normal. In fact, that is one of the biggest visceral joys of this car, and any car that rev-matches. It's a great sound, and I try to get it every time I slow down and shift into 2nd. I know, I'm immature, but it's little joys like this that make life fun.

Lastly, I usually shift the car downwards myself. But I actually never shift down into first. I always let the car go from 2nd to 1st on its own. This is a historical habit for me. My other car ('03 eclipse) will let me downshift into 1st, but it will basically jerk the car to a crawl if I'm doing it too early; it's pretty violent. So I always let the Eclipse go down on its own, and thus I let the Z do the same. I've found myself accidentally shifting the Z down into 1st, but I've never had it suddenly jerk or heave at all; so it's likely far more safe than with my other car.

Find a large parking lot of long stretch or road and just go up and down the gears as you speed up and speed down. You'll get used to it.

The only thing I want to stress, is if you do get into the habit of downshifting with the paddles, don't RELY on the engine braking that will naturally happen as you do; be kind to anyone behind you and use your brake so they see your brake lights and know you're slowing down. I use this for braking a lot, but I always use my brake to some degree when someone is anywhere near behind me.