Google Tag Manager’s Preview & Debug mode allows you to browse the website with your GTM container installed and preview how Tag Manager will implement your Tags, Triggers and Variables.

However, it can take a little while to get used to the layout and to understand exactly what is going on, so we have written the following guide to help make it a bit simpler. Before we carry on, it’s important to understand that the preview mode is cookie based, so any activity will only be based from your machine. This is especially important to remember when you have not published your container yet. You can, however, share your view of the debug mode to other people; this will still not be viewable by general users.

We have also written a guide on What is Google Tag Assistant and How to use it Properly , so check that out as well.

HOW TO ENABLE AND DISABLE PREVIEW & DEBUG MODE

In your Google Tag Manager container, choose the workspace you wish to preview and you’ll see a button called Preview – it’s next to the Submit button in the top right-hand corner of the screen. Click the preview button, there’s normally a pause, then the page will refresh and a large orange box will appear at the top of the container. This tells you that you are now in preview mode. 

Read the full resource here...