In this short video, you can find what code you need to make your html5 banner works on google campaign manager 360 (old name DoubleClick).
The code is below and detailed instructions you can find in the video above:
<meta name="ad.size" content="width=970,height=250">
<script src="https://s0.2mdn.net/ads/studio/cached_libs/createjs_2019.11.15_min.js"></script>
<script src="/970x250.js"></script>
<script>
var clickTag = "";
</script>
<a href="javascript:window.open(window.clickTag, '_blank')"></a>
Don't forget to check your html5 ads in google validator at the end.