if there's no plugins and I gotta do hacker linuxy stuff myself please be as detailed as possible thank you
For auto embedding of videos or any other type of media use AutoMedia:
https://community.mybb.com/mods.php?action=view&pid=286
For Adsense, a plugin isn't necessary. Go to your Adsense, copy the ad code.
Now go to Admin CP > Templates & Styles > Templates > Choose the theme you're using
Now choose your header, footer, or wherever else you want the ads to appear. Paste the Adsense code in those templates.