Setting up the tag: Create a new tag configuration > custom HTML tag
Paste your provided OP script into the HTML field
Enable "support document.write"
Ensure this tag has the highest firing priority as possible
Check the "Only fire the tag in published containers"
Set Tag Firing Options to "Unlimited"
Setting Triggering Rule: Trigger Configuration > Trigger Type
Set the "Page View - DOM Ready" type
Set trigger to fire on "All DOM Ready Events"
Save and Publish the new container and you're all set!