Oh so you have managed to boot into the O/S?
1) Swipe left to get to the app list,
2) scroll down until you see the gear icon (that is the icon for settings)
3) Scroll all the way down to the bottom and region is the 19th entry (language is the 18th).
4) the top box is for country and tap on that
5) United kingdom is the 9th entry from the bottom and USA is the 8th.
6) Tap on either
7) this will bring you back to previous screen, where at the bottom you should see a button with blue* (or what ever the accent/theme colour is) writing and tapping on the button will restart the phone.
8) You phone now should start up in english, go back to region again to change to your preferred region.
If it does not, then go to language:
1) Tap on the + icon
2) English (Australia) is the 14th Tick box
3) Tick it and press the tick on the app bar on the bottom
4) You will now go back to the language screen, where you should see a button with blue*(or what ever the accent/theme colour is) writing underneath and tapping the button will restart and your phone will be using English (Australia)