If you are into Google Ads and Meta Ads, you must already be aware how important first party data has become when it comes to conversion tracking. And one of the best ways of pushing first party data is to retrieve information from the Data Layer. However, not all websites will be configured in a way that automatically pushes this information into the Data Layer. In that case, you will have to use Custom HTML and Custom Javascript in Google Tag Manager (caution: advanced use case!) to get this done. I show the detailed step-by-step process in this video.