Note: This article is for sites that use the embed tag. Shopify users don't need to install a tag.
You can install Promolayer on every page of your site by adding the Promolayer code to Google Tag Manager (GTM) as a Custom HTML tag.
Steps
Log in to Promolayer, open the dropdown menu at the top right, and click Install code.
Copy the code under Google Tag Manager installation.
Use this code, not the code under Standard installation. The two codes are different.
In Google Tag Manager, create a new tag named Promolayer with the tag type Custom HTML.
Paste the code you copied in step 2 into the Custom HTML tag.
Select the trigger All Pages.
Save the tag, then publish your GTM container so the change goes live.