How to change the navigation button order on a Samsung phone
This tutorial will show you step by step how to change the navigation button order on a Samsung phone (e.g., the “back” button from right to left).
For example, the “back” button is, by default, on the right side of the navigation bar, but you can move it to the left.
You can change your navigation button order from Recents, Home, and Back to Back, Home, and Recents.

Steps
1. Open your phone's settings.

2. Tap on Display.

3. Scroll down to Navigation bar and tap on it.

4. Select the desired button order. You can also switch to swipe gestures if you want.

That's it.
5. You can close settings now.
Related:
How to get the Google search bar back on a Samsung phone
How to empty trash on a Samsung phone (step by step)