Each of the valve cover vent covers where the small hoses connect have a tiny hole into the valve cover.
It's just that simple, the manifold vacuum draws the engine fumes through these two tiny holes
and the fumes/oil vapors are burned in the combustion chambers.
The NeedsWings oil catch can replaces these 2 hoses with longer ones that go to the intake of the catch can.
There is then another hose from the catch can to the "Y" connector, the other port of the "Y" connector is capped off.

Yes, I can hear the hissing at the connector point on the covers even without using Woody's hose method, it is considered "normal"

The LARGE hose on the driver's side vent cover is the "equalization" hose, it connects BEFORE the throttle body and serves to equalize the internal
pressures with the outside atmosphere. DO NOT CAP THIS HOSE OFF !!!
Ask me how I know : I thought it redundant and capped both ends once, you never heard such noises from an engine like I had.
I swore it was my water pump going bad, once I put the hose back on, all was well again.