'Relate' organised paper with volunteers at home (9)
I believe the answer is:
appertain
'relate' is the definition.
(thesaurus)
'organised paper with volunteers at home' is the wordplay.
'organised' is an anagram indicator.
'with' says to put letters next to each other.
'volunteers' becomes 'ta' (abbreviation for Territorial Army).
'at home' becomes 'in' ('in' can be similar in meaning to 'at home').
'paper' anagrammed gives 'apper'.
'apper'+'ta'+'in'='APPERTAIN'
(Other definitions for appertain that I've seen before include "Belong, relate (to)" , "Concern" , "Bear on" , "Be relevant to" .)