Step 1: Backup your theme
Note: The app will apply a few changes to your theme. Before “integrate theme”, We strongly recommend you to create a backup theme. To create a backup, you go to Online Store > Themes > Actions > Duplicate:
The Integrate theme page will be shown. You select a theme to apply the filter, and click on the Apply Filter button:
After integrating theme, The new filter will be applied to this theme. You should preview and check this filter in this applied theme in the storefront.