You use the slip fittings that should come with the pump, unless you got the version which does not have it.
If thats the case, you probably need to go on amazon, contact CNZ Lighting, as i think they are a main distributor for jebao, and ask if you can buy the slip fittings for your pump seperately.
But it would look like this:
Then just use pvc cement, and glue to the slip fittings.
The o-ring would go on the inlet, and then a compression ring would compress the oring on the inlet and slip fitting forming a tight seal.
Remember do not forget the oring, this is the #1 reason why people complain it leaks, but its like a Union, just need a good amount of tightness on the compression ring, and make sure your pvc cement is cured and applied properly.