Summary This guide is for beginners, intermediates who know the basics of web applications, web servers & digital advertising. Google Tag Manager helps you to effortlessly implement all your existing marketing tags without cluttering it up in the source code of the website. This guide will help you understand how you can perform an effortless migration of the hardcoded Google Analytics implementation from the website into Google Tag Manager. Intro of Google Tag Manager   Google Tag Manager is a free and user-friendly tool which helps you implement all your marketing tags on the website (or mobile application) without explicitly having them to be placed on the source code of the website. You can easily manage adding, editing or deleting your tags from the website