Adding to Google Tag Manager
How to add the script to your GTM custom HTML field
Step 1 : Sign into your Google Tag manager account and "select your workspace"
you can find Tag Manager here : tagmanager.google.com
Step 2 : Click on "Tags" from the left and "New"
Step 3 : Click on "Tag Configuration"
Click on the highlighted block, not on ‘learn more’
Step 4 : Find "Custom HTML" from the list
Step 5: From the Visitorscheck dashboard, select and copy all the text in the black box
You can find the code on your dashboard