If you want to customize Krypton WordPress Theme, It’s recomended to use Child Theme feature. Krypton WordPress Theme supports Child Theme. Krypton child theme allow you to make changes without affecting the original krypton theme’s code, which makes it easy to update your parent theme without erasing your changes. By creating a child theme, you create a separate set of files that you can use to customize the theme without affecting the original theme at all. Not only does this make updating easier, it also makes sure that you will never ruin your original theme as you are never actually modifying the files. You can always turn off your child theme and fall back on the original. For more detail about Child Theme you also can read https://codex.wordpress.org/Child_Themes
Installing Child Theme
Installing Child Theme is just like installing any other WordPress theme. Install Krypton Child Theme after you install the parent Krypton Theme. Find the zipped child theme named “krypton_wp_child.zip” in the zipped downloaded file from Themeforest.
If the installation success and the child theme is activated, you’ll see the both parent and child theme in theme list. The child theme will be named “Krypton Child”.
After the child theme is activated, you could edit the child theme style through menu “Appearance” > “Editor” in admin area.