Google Adsense

I can’t figure out where the HTML codes are, so I can put in my google adsense code… Help?!

I would like to help you. As I know if you want to paste any of yours HTML-code you should use HTML-Component.
Here`s example of sending data between HTML-component and your Wix-site:

As for Google Adsense - here is an article how to work with Add Sense and set up it in Wix Editor:
https://support.wix.com/en/article/adding-and-setting-up-the-google-adsense-app