How to handle external components with EAGLE CAD ?

[kuki1975]

Hello,
I'm started to design a small circuit with eagle.
Does anyone has a Idea how to handle external components which are not on the PCB like Poti, Jacks, 3PDT with the eagle schematic ?
Also I don't really know how to handle signals which doesn't go over the board like the Input Signal which
goes directly to the 3PDT.

I would like to keep all the Signals and external components in the schematic for better Documentation and Debugging.

Can anyone help ?
Regards,
kuki