Contribution from people supporting party (8)
I believe the answer is:
donation
'contribution' is the definition.
(I know that contribution can be written as donation)
'people supporting party' is the wordplay.
'people' becomes 'nation'.
'supporting' means one lot of letters go next to another (in a down clue, some letters go below others).
'party' becomes 'do' (do can informally mean a party).
'nation' put after 'do' is 'DONATION'.
'from' acts as a link.
(Other definitions for donation that I've seen before include "presentation" , "Gift of money as to charity" , "Gift or contribution" , "present" , "An offering or charitable gift" .)