Yon - you can get the tags for each placeholder from your ad tester menu, but it's very possible that this will still not fix the issue that you're having. The problem is that React will load assets client side, while ads are loaded server side. This means your content is essentially overwriting your ad setup.
here's the link to the placeholders page in your dashboard if you'd like to try and manually insert ads ->https://pubdash.ezoic.com/ezoicads/adpositions/placeholders
If not, we can enable JS based integration options with Ezoic - It'll be much lighter on features, but you should be able to get in content ads showing on your site.