I used to use a Android phone, where the back button was on the left side of the screen, them home button in the middle and then active apps.
When I bought Oppo Find X5 I realised that the buttons are in the reversed order: active apps, home and then back. It was (like for me) quite annoying but there is a solution to change it!
Click Settings, scroll down a bit and select Additional Settings…
…then select System Navigation…
…and finally select a buttons layout you want:
