In this video I connect a guitar effects pedal to an analog mixer using the AUX SEND/RETURN to create an FX LOOP. You could connect a variety of different Effects (FX) devices or sound processors this way.
Connect AUX SEND to FX INPUT and FX OUTPUT to AUX RETURN
This creates the FX "LOOP"
In the video I am using a MONO effect, but you can also connect STEREO effects by using both the L and R AUX RETURN.

***NOTE: Some guitar pedals will not handle a line level signal well. It may distort or sound poor, and it could cause damage to certain older pedals. You may be able to compensate by decreasing the level sent to the pedal by adjusting the AUX SEND so that the signal is no longer overloading (clipping) the pedal. If this does not work, then you will need a reamp box to connect your guitar pedal.

Equipment:
Mic: Shure SM57
Monitor/Speaker: Peavey PR10P
Mixer: Behringer Xenyx X1204USB
FX pedal: MXR Analog Chorus M234