Connections for Panel Mount 12VDC Power Supply
This power supply is intended to be mounted somewhere inside your enclosure.  The screw terminals are intended to be used with either stripped wire ends or spade crimp connectors.

In other words, just use wires to connect the power supply to both the incoming power as well as to your circuit.

We normally just use stripped wire ends.  Stranded wire but not tinned.  The pressure plates are designed to spread the wire strands out over a large surface area and provide long-term clamping pressure.

If you tin the wires, all of the clamping force is concentrated over a very small area and the solder between the strands will cold-flow.  This results in the connection becoming loose over a long period of time.