At this point, I don't recommend people use the Tesseract theme. It's really a dead end theme.
A better alternative is the free Astra Theme, which allows you to edit the footer with ease.
Also, you may need to install and run a free plugin named Switch To Astra to make all your page builder built pages work out of the box.
And if you really want to see something amazing, check out the free Astra Sites plugin.
I have tutorials on all of this.
This child theme will only work for you if you don't already have a child theme on your website.
Also depending on when you installed the Tesseract theme, the child theme from my website may not work without making a small adjustment.
It's really a cat and mouse game with these guys. Essentially if the folder name for the parent theme has changed, it needs to be changed in the style.css file in this child theme.