Rested when a bed's made up (5)
I believe the answer is:
based
'rested' is the definition.
(both can mean located or positioned)
'a bed's made up' is the wordplay.
'made up' is an anagram indicator.
'a'+'beds'='abeds'
'abeds' is an anagram of 'BASED'.
'when' acts as a link.
(Other definitions for based that I've seen before include "Located" , "Positioned" , "foundation" , "(Of aircraft) stationed" , "Founded, grounded" .)