How do I unlock and start my car?

It's all done through your Maven app.

At the time of your reservation, stand near the car with your app open and Bluetooth turned on. After you complete the mandatory Pre-Trip Report, the in-app key will turn blue when the car is connected.

To start the car, step on the brake, press the start button, and you're good to go. Don't forget to push the button again to turn the car off.