Thank you very much for replying, @Erin; only one additional question more:
Where to put the Tag exactly - before, or behind the Google-Analytic-Script?
At the moment it would look like that:
<link rel="alternate" hreflang="de-at" href="http://s-schnitzl.weebly.com/" />
<script>
(function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
(i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
})(window,document,'script','https://www.google-analytics.com/analytics.js','ga');
ga('create', 'UA-82833599-1', 'auto');
ga('send', 'pageview');
</script>
