That description only applies to SMPS, it is quite different in linear supplies. however, I think this is what you are needing:
1. Filter
This is an EMI filter and possibly a surge supressor. SMPS tend to produce sharp edged signals which are rich in harmonics and could conduct down the power cord, using it like an antenna, and cause interference to radio, TV and other sensitive equipment. The filter is there to reduce the interference down to an acceptable level.
2. Rectifier
Most SMPS use a DC supply to the switching stage, this first rectifier would be at the line frequency (usually 50 or 60Hz) to convert the incomng line AC to DC.
3. Power Switching
Would be the part of the circuit that chops the DC at high frequency, making it look more like AC again. By using a higher frequency than the incoming line, the physical size of the transformer beomes much smaller. This is why SMPS are smaller and lighter weight than conventional supplies. The construction of the transformer determines the voltage the PSU produces.
4. The high frequency pulses from the transformer need to be converted back to usable DC again. That is the job of the second rectifiers. They are usually Schottky or fast switching diodes because normal types are not suitable at high frequencies.
5. Detection circuit
I assume this to mean the feedback circuit. A power supply would normally be expected to give a regulated output. Under heavy loads the output would tend to drop because of the strain and losses in the earlier stages so the output is compared to a fixed regulated voltage and the difference (called the error voltage) is fed back to the switching stage to make it 'push harder'.
I've been very generic in those explanations, there are many types of power supply and they all work in slightly different ways.
Brian.