Found these instructions on-line:
1. Put the water into the skimmer chamber until the water level is up to 8 in., switch off the
air valve completely, start the power. After seconds, turn on the air valve as soon as the
pump works properly. When the bubbles coming out perfectly, replace the air valve by the
silencer.
2. Adjust the water outlet, so that the bubble stopper comes out a little bit from surface.
3. If power shuts off, restart from step 1.
Not sure if you need the owners amnual but here's a link:
Reef Octopus Protein Skimmer BH 1000