...a list of the ten most common and effective strategies resorted to by the agendas "hidden" to establish a manipulation of the population through the media.
I understand the beginning and the end of above text, but the middle is incomprehensible to me.
It is rather convoluted, isn't it?
... a list of (what?)
the ten most common and effective strategies (describe them!)
resorted to (by whom? by what?)
by the agendas (which ones?)
"hidden" (why?)
to establish (what?)
a manipulation (of whom? of what?)
of the population (by what ways?)
through the media.
The part that starts with "resorted to" is called a relative clause, and a connecting relative pronoun can be restored to make it read
... a list of the ten ... strategies which are resorted to by...
The "resorted to" is a past participle (pointing to passive voice) from the verb "resort [to]" meaning "use in desperation" or "use as final available option".
