The power button on the right side of phone is longer so it is easier to press while holding the device in one hand, according to the images and the people. (bloomberg.com)
As for the fingerprint sensor, it is located on the power button on the right side of the device. (dealntech.com)
Below the 5.5 - inch display is a pill - shaped fingerprint sensor, with power and volume buttons on the right side of the phone. (zdnet.com)