You can customize the settings by clicking on a three-line settings icon.
On your computer, it would be to the left of the board.
On your IOS App the Board settings will be in the Upper right corner.
Here you can customize board style, sounds (on or off), auto-queen promotion, indication of the opponents move and more. You can also ask World Chess to show (or not) legal moves.
Once you finished setting up the playing space, just click ‘Save and close’ and the settings will be saved. You can change them anytime.