Its not a bh 1000. Its an older version that they likely don't make anymore.
I can't really see what pieces you have laying around inside it, but assuming they are all there there should be a clip with a screw that slides in those black slots to keep it secured to the tank.
After that it's really just plug and play. Fill it about halfway, plug it in, plug the hole on the black tube that you're holding until it draws enough water to flow through, and then release it.
The box on the top right will control the amount of skimmate you get. The higher it is, the dryer your skim will be.
There are likely some screens that you will have to play with to get in the right places. But I would need some more pictures to help with tjat.
Mebbid's Fishtopia: Various builds
"The simplest explanation for some phenomenon is more likely to be accurate than more complicated explanations." -Occam's razor