For example, painting walls in office, very enthusiastic (6)
I believe the answer is:
ardent
'very enthusiastic' is the definition.
(I've seen this before)
'for example painting walls' is the wordplay.
'for example' becomes 'den' (I am not sure about this - if you are sure you should believe this answer much more).
'painting' becomes 'art' (I've seen this before).
'walls' indicates putting letters inside (to 'wall' can mean to contain).
'den' inserted within 'art' is 'ARDENT'.
'in office' is the link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for ardent that I've seen before include "Intensely devoted" , "Hot" , "Zealous - ranted (anag)" , "Burning with emotion" , "Fiery and zealous" .)