One’s fired up here to hold flat-warming party? (6,3)
I believe the answer is:
launch pad
'one's fired up here' is the definition.
(where a rocket may be fired up)
'hold flat-warming party?' is the wordplay.
I cannot quite see how this works, but
'flat' could be 'pad' (a person's home) and 'pad' is found in the answer.
'party?' could be 'l' and 'l' is found within the answer.
This explanation may well be incorrect...
'to' is the link.
(Other definitions for launch pad that I've seen before include "that can kick-start career" , "Structure on which a rocket sits" , "platform" , "explorer's starting place" , "Rocket's starting point" .)