Finish the job; start navigating in rising tide (3,2)

'finish the job' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.

'start navigating in rising tide' is the wordplay.
'start' suggests taking the first letters.
'in' means one lot of letters goes inside another.
'rising' says the letters should be written backwards (going up in a down clue).
The first letter of 'navigating' is 'n'.
'tide' reversed gives 'edit'.
'n' put within 'edit' is 'END IT'.

Can you help me to learn more?