First during summer month to get to river (9)
I believe the answer is:
inaugural
'first' is the definition.
(I know that first can be written as inaugural)
'during summer month to get to river' is the wordplay.
I cannot really understand how this works, but
'during' could be 'in' (e.g. during February means in February) and 'in' is located in the answer.
'month' could be 'aug' (abbreviation for August) and 'aug' is present in the answer.
'river' could be 'ural' (I've seen this in other clues) and 'ural' is found in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for inaugural that I've seen before include "President's address" , "Of an opening ceremony" , "Marking the beginning of, eg, an institution" , "It may be delivered" , "First address" .)