It's fashionable to be on board highest deck to get a chance to take a selfie, perhaps (5-2)

'get a chance to take a selfie perhaps' is the definition.
I can't judge whether this definition defines the answer.

'it's fashionable to be on board highest deck' is the wordplay.
'it's fashionable' becomes 'hot' (hot can mean fashionable or trendy).
'to be on board' indicates putting letters inside (inserted letters are taken on board).
'highest deck' becomes 'poop' (poop deck is a kind of deck. I am not sure about the 'highest' bit.).
'hot' inserted inside 'poop' is 'PHOTO-OP'.

'to' acts as a link.

Can you help me to learn more?