Provide as an instalment (3,2)
I believe the answer is:
lay on
'provide' is the definition.
(I've seen this before)
'an instalment' is the wordplay.
I cannot really see how this works, but
'an' could be 'a' and 'a' is found in the answer.
The remaining letters 'lyon' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
'as' acts as a link.
Can you help me to learn more?
(Other definitions for lay on that I've seen before include "instruction for Macduff" , "Provide (food, etc)" , "Provide (something)" .)