Where to connect Adsense to custom google search created?

Question

Google Adsense

Created a search for SPP from Google for the site. My adsense identifier was defined in the settings, but then I don’t know what actions to take. Google wants me to read how to do it, and swears at the FAQ in which everything is so superficial that it’s even embarrassing for him. I go into the acc andsense, there is a feature to create a custom search (??? why duplicate the functionality?) in which you can create a new search. As a result, I still didn’t figure out how to attach adsense id to the NGN. If anyone has come across this recently, please let me know, I would be very grateful.
Thank you.