To change your site's Theme:
Log into your Shift4Shop Online Store Manager.
Go to Settings > Design > Themes & Styles.
Then, click on the Change Theme button.
You will see all of the various themes that are available for your store. To install a theme, click on it to open up its respective preview screen. Once you're ready to install the theme, click on the Download Theme button. The Shift4Shop interface will download the theme and you'll be asked if you'd like to apply the template.
Clicking "Yes" to this screen will effectively update your site's live theme.
Clicking "No" will merely install the theme without applying it to the live site. The theme will then be found in the "Installed Themes" section of the page. When you click on the installed theme, you will have the following options:
This will show you a preview of the theme as it would appear on your live store.
This option will re=install the theme from scratch, thereby removing any customizations you may have applied to it.
This button will remove the theme from your Installed section. (Make sure the theme is not applied)
This option will apply the theme and make it live on your store.