Copy the GHL Customizer code snippet from the GHL Customizer dashboard.
NOTE: You may want to remove any pre-existing Custom CSS as this may interfere with the GHL Customizer script. If you use code from multiple sources or 3rd party service providers and experience any issues, please submit a Support Ticket.
Switch back over to the GHL Customizer browser tab and start experimenting with the different features. After you've made some changes, click the blue "Publish to live" button in the GHL Customizer then switch over to your HighLevel browser tab and refresh it to see the customizations you've made. Repeat this step until you have added all of the customizations you want to implement.
Learn more about the GHL Customizer Features: https://help.themarketerstoolkit.com/category/6/ghl-customizer-features