The entire contents of the packet? (8)
I believe the answer is:
boatload
'the entire contents of' is the definition.
The definition suggests a singular noun which matches the answer.
'packet?' is the wordplay.
I cannot really understand how this works, but
'packet?' could be 'boat' (packet is a kind of boat) and 'boat' is found in the answer.
The remaining letters 'load' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
'the' is the link.
Can you help me to learn more?
(Another definition for boatload that I've seen is " All the people Michael rowed ashore? - too bad, Al! (anag)".)