How to stretch 2 columns in a flexbox


I have a flexbox with 2 columns. But it is now alligned to the left instead of the center.
So the left column is perfect, but I want the right column to be more alligned to the rightside. Otherwise there is a huge white space at the right side of the screen.

I tried stretch and justify content, but it didnt work.

Anyone know what to do?

Thank you Stan! Your video helped a lot