Please help distribute these pamphlets to the people who came.
Literal
Come-give-me-[attributive-た] people [to-に] this pamphlet [object-を] distribute [nominalizer-の-を] help-please.
A layered sentence with a nested nominalization. の turns 配る ('distribute') into 'the distributing,' which is then the object of 手伝う ('help'). 来てくれた人 is a relative clause with ~てくれる inside — 'people who kindly came.' パンフレット is the katakana loanword.