This is what your home screen might look probably with a different wallpaper
Now press and hold the recent button for additional option.s
when you press the menu button you will find the 4 options and one of them will be preferences as shown in the below screenshot, you need to select ‘preferences’ option.
In preferences you have the toggle to lock the screen layout, if you enable the toggle, the layout will be locked and if the toggle is disabled, the layout will be unlocked.
If you try to change the position of app or change the layout you will get the error like in the below screenshot.