How to make the canvas background transparent

I am trying to create a GUI in a separate scene that is displayed on top of the game, the problem is that the canvas is not transparent and covers the entire game screen.

window.onload = function () {
game = new Phaser.Game(gameWidth, gameHeight, Phaser.AUTO, “”);
game.state.add(‘Boot’, boot);
game.state.add(‘Preload’, preload);
game.state.add(‘TitleScreen’, titleScreen);
game.state.add(‘PlayGame’, playGame);

gui = new Phaser.Game(gameWidth, gameHeight, Phaser.AUTO, "");
gui.state.add('Boot', guiboot);
gui.state.add('Preload', guipreload);
gui.state.add('Screen', guiscreen);


new Phaser.Game({ transparent: true })

Thanks but I have solved it. it is better to use gui plugins than to create a separate scene.