American soldiers first to enter the lists (5)
I believe the answer is:
menus
'lists' is the definition.
(menu is a kind of list)
'american soldiers first to enter' is the wordplay.
'american' becomes 'us' (abbreviation for United States).
'soldiers' becomes 'men' (men can mean a group of soldiers).
'first to enter' is a charade indicator (letters next to each other) (some letters go first).
'us' after 'men' is 'MENUS'.
'the' acts as a link.
(Other definitions for menus that I've seen before include "Bills of fare" , "Restaurant lists" , "List of dishes available" .)