I need to add a Copyright line to my footer

Hi,

I need to add Copyright text to the footer of my blog. As I don’t understand the code in the footer.php line I am not sure what I need to add there and where exactly. I suppose I need to create a child theme, but I don’t know how to do this.
Could someone please help with the simplest way to add the copyright line?
My blog runs on the Expound theme and the site is http://thebohochica.com/

Many thanks!