Embed user details/airtable data into custom code

Hi everyone,

I want to use the features of site called Lou Assist to create one time pop ups/tours etc

I am inserting custom code into my page and want to use user/airtable data to have a custom user ID to prevent pop ups occurring more than once.

The code is this:

<script src="//run.louassist.com/v2.5.1-m?id=xxxxxxx">
LOU.identify('UserID')
</script>

I have tried everything but am not having much luck - how do I make the User ID data from either logged in user email and/or from airtable (users are connected to airtable)?

Thanks!