Quick and easy Keying question (pics inside)

How can I make the black night of this shot transparent??
basically trying to super impose this over a motorbike exhaust and am having great difficulty with my lack of experience with fusion - wand mask seems to not want to work for me... just makes the whole picture transparent.
Thanks for any help
basically trying to super impose this over a motorbike exhaust and am having great difficulty with my lack of experience with fusion - wand mask seems to not want to work for me... just makes the whole picture transparent.
Thanks for any help