Diagram of sequences from fellow depressed companion with talent (4,5)
I believe the answer is:
flow chart
'diagram of sequences' is the definition.
'flow chart' can be an answer for 'diagram' (I've seen this before). I am unsure of the 'of sequences' bit.
'fellow depressed companion with talent' is the wordplay.
'fellow' becomes 'F' (abbreviation - of a society etc.).
'depressed' becomes 'low' (synonyms).
'companion' becomes 'ch' (Companion of Honour).
'with' is a charade indicator (letters next to each other).
'talent' becomes 'art' (I've seen this in another clue).
'f'+'low'+'ch'+'art'='FLOW-CHART'
'from' is the link.
Can you help me to learn more?
(Other definitions for flow chart that I've seen before include "Diagram representing sequence of operations" , "computer diagram" , "System movement diagram" .)