In your Google Tag Manager console, click on New Tag.
Here, you can add a tag name and then click on the Tag Configuration box.
Choose Custom HTML from the list of tag types.
You then need to paste the tracking code into the HTML text area.
If you don't have the tracking code, you can find it in your ActiveIQ account by going to Configure -> ActiveIQ Code.
Once the code is added, we need to assign a trigger to it. Click on the Triggering box and select All Pages.
You can now save your changes.
Changes saved in your Google Tag manager still need to be published to make them public, so let's click on the Publish button.
(Optional) you can add a name and description of this change.
You will then be shown a summary of changes made in this version of the tag.
Once confirmed that the changes are live, your tracking code will be added to every page of your site.