Right now’s when one puts it on show (8)
I believe the answer is:
presents
'right now's' is the definition.
'present's' can be an answer for 'now's'. I'm not sure about the 'right' bit.
'one puts it on show' is the wordplay.
I cannot quite see how this works, but
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is found within the answer.
'on' could be 're' ('on' can be mean 'with reference to') and 're' is found in the answer.
This may be the basis of clue (or it may be nonsense).
'when' acts as a link.
Can you help me to learn more?
(Other definitions for presents that I've seen before include "tips" , "Awards formally" , "Hands over formally" , "Introduces" , "Offerings" .)