On top of having a Server Side container, you will need a web container that will listen for triggers (button clicks etc) on your website and can then send tags to your server side instance.
Below are instructions for setting up a new web container as well as for migrating an existing container to send tags to your new server side instance.
How to install a new web container
Under the same Google Tag Manager account, create a new container and select the Web option.
You will then be displayed the instructions for installing this web container onto your web page. Add the scripts displayed to every web page on your site in the appropriate place and you will now have Tag Manager installed on your website.
The next step is to follow the instructions in the section below about configuring your tags for server side GTM.
How to install from existing web container
These instructions will help you to migrate tags in your existing web container over to your server side container.
Before making any changes to your web container, it is highly recommended that you either create a backup of your existing container, or create a new container which has the configuration copied over from the old container. For more information, please read how to backup your web container.
The next step is to note down all of the existing tags you have implemented and what website events they belong to. For example, clicking the purchase button on a product page may trigger a Google Analytics tag, a Facebook tag and a Google Ads tag.
In the example above, the 3 tags sent in the web container will need to be moved across to the server side container. For information on how to set this up, please refer to configuring your tags on your server side container section.
Once the 3 tags in the example above have been ported across to the server side container, 2 out of those 3 tags can be removed from the web container, with the remaining one reconfigured to send to your server side container. For more information, please see the configuring web container tags to send to server side GTM section.
Summary: When migrating your web container tags to server side, it is important to keep the end goal in mind. The end goal of the migration is that for each trigger in your web container, you only need 1 tag firing which sends it to the server side container. It is then the responsibility of the server side container to forward that tag onto the appropriate platforms (Google Analytics, Google Ads, Facebook etc).
