How do I center Falling shapes example?

Hi everyone, hope you are doing great,

I am decided to make a tetris like game, and started using falling shapes game in c3 as a start/guide

The file is super commented and "easy" to follow, but I cant place the main game in the center of the screen.

Ideally I would love to center it in a wide screen, and if seen on mobile, cut the screen from left and right at the same time.

Any suggestions?

Here is where I get really lost

This is what I would like to have:

I dont know if I should center the game, or place graphics outside and how to make them visible from the middle (I do get this when the game is on the left side)

Hope what I am saying makes any sense! Thanks in advance