If you don't have a Google Tag Manager account already, you can create one for free at Google Tag Manager.
In this guide we will go through how to install the segment pixel in Google tag manager.
Install the Match2One segment pixel
1. Copy the Match2One segment script
2. Go to tagmanager.google.com, log in to your account and select the container for your website
3. Select Add a new tag
4. Select Tag configuration -> Custom HTML Tag
5. Paste the script you copied earlier into the HTML text area in Google tag manager
6. Scroll down and click triggering -> select All pages
7. Select Add exception
8. Choose the trigger you are using for the conversion script - hit Save
(If you are not using a conversion script you can skip this and proceed to step 9)
9. Name your trigger and click Save -> Publish -> Publish once again -> optionally you can add a description, or skip this step
10. Congratulations, your segment pixels are firing!
Also make sure to install the conversion script: