Affirm.js code with Enfold

Hello
Our website uses Affirm financing and we want to install their modal javascript. This is the code they provide with instructions to insert it into the global page template.

How we do go about this and what would happen on future theme updates? we are not using a child theme.

<!– Affirm –>
<script>
_affirm_config = {
public_api_key: “YOUR_PUBLIC_KEY”,
script: “https://cdn1-sandbox.affirm.com/js/v2/affirm.js&#8221;
};
(function(l,g,m,e,a,f,b){var d,c=l[m]||{},h=document.createElement(f),n=document.getElementsByTagName(f)[0],k=function(a,b,c){return function(){a[b]._.push([c,arguments])}};c[e]=k(c,e,”set”);d=c[e];c[a]={};c[a]._=[];d._=[];c[a][b]=k(c,a,b);a=0;for(b=”set add save post open empty reset on off trigger ready setProduct”.split(” “);a<b.length;a++)d[b[a]]=k(c,e,b[a]);a=0;for(b=[“get”,”token”,”url”,”items”];a<b.length;a++)d[b[a]]=function(){};h.async=!0;h.src=g[f];n.parentNode.insertBefore(h,n);delete g[f];d(g);l[m]=c})(window,_affirm_config,”affirm”,”checkout”,”ui”,”script”,”ready”);
// Use your live public API Key and https://cdn1.affirm.com/js/v2/affirm.js script to point to Affirm production environment.
</script>
<!– End Affirm –>