Hold the power button to turn on your iPhone. Swipe the slider right to begin activation.
Once connecting to the wifi network, you'll be prompted to enter your phone number
you can add a password to your phone, you can use the touch id or passcode option to keep your phone secured
you can backup using iCloud or iTunes or from a previous android phone or you can just set it up as a new iPhone
You can set up Siri now or you can do it later. You can select the voice option for using Siri.