Go up higher in short descant arrangement (6)
I believe the answer is:
ascend
'go up' is the definition.
(I know that ascend is a kind of go up)
'short descant arrangement' is the wordplay.
'short' means to remove the last letter.
'arrangement' is an anagram indicator.
'descant' with its final letter removed is 'descan'.
'descan' with letters rearranged gives 'ASCEND'.
'higher in' acts as a link.
I am not very happy about this link. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for ascend that I've seen before include "Mount" , "Scale" , "Dances (anag.)" , "Climb, go up (6)" , "Get higher" .)