I decided to make this lesson as it very big headache when you like adobe animate and need to implement google ads specification but something always not working.
I explained in detail what to do in the video - but if you just need to copy-paste from somewhere createJS library and metatags - you can find them here below:
1.metatag - <meta name="ad.size" content="width=300,height=250">
2.library - <script src="https://s0.2mdn.net/ads/studio/cached_libs/createjs_2019.11.15_min.js"></script>
Don't forget to check your html5 ads in google validator at the end.
Google specs for html5 banner are not something complicated as you can see. Hope it was useful.