Step 1:
Created “atahualpa.3.7.10-child” directory in wp-content/themes folder.
Step 2:
Placed the style.css file (only one file) in that directory and it is:
/*
Theme Name: Atahualpa 3.7.10 Child
Description: Child theme for the Atahualpa 3.7.10 theme
Author: Your name here
Template: Atahualpa 3.7.10
*/
@import url(“../atahualpa/style.css”);