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Log into your BigCommerce account as an administrator.
Navigate to Storefront Design > Design Options, and then click the Footer Scripts tab.
Paste the script in the Footer:
For Proactive Chat V1.0:
Code Block <script type="text/javascript" src="https://pop0-apps.mycontactcenter.net/webchatscripts/telaxdemo10/icr/0e8af7f4-82dc-44d5-a557-b49ae49a49da/icr.js"></script>
For Proactive Chat V2.0, copy the Proactive URL as shown in Proactive Chat v2.0
Save your changes.