When I wash behind the faucet and dishwasher vent water leaks under the sink. I have identified the leak is from around the vent site. There is no leaking from the vent itself. But I think the vent needs to be tightened from under the sink. Does anyone have a diagram/schematic showing me how all the pieces fit together under there? Should I use a gasket or just silicone to seal around the edge of the vent? Thanks

That "vent is called a "Air Gap". Look under the air gap and snug up the nut. That should be ebough. Tom