In order to do a stereo set-up, you will need a couple of things. There are numerous different ways to accomplish this, but I'll use my set-up as an example.
At the very least you need some sort of stereo effect to split the signal into left and right. This could be either a stereo pedal (chorus pedals and delay pedals often have this option), or a stereo effects rack unit. I have all three (1) a stereo delay pedal, (2) a stereo chorus pedal, and (3) a midiverb rack unit that is stereo. Right now I'm not favoring the midiverb - instead I use my old Boss chorus pedal to split my signal.
The next thing you need is either two amps or a pre-amp and a separate stereo power amp.
Here's what I do: I run two effects loops - one in front of the amp (i.e., not in the loop), and one in the loop.
I come out of effects send on my main amp (an F-50) and go into a rack tuner. Then rack tuner > rack reverb > delay pedal > chorus pedal.
The chorus pedal has a left and right output. The left output goes into the effects return of the F-50, and the right output goes into the effects return of my other amp (a DC-3).
This way the pre-amp of the F-50 is driving the power amps in the F-50 and the DC-3. (When you go into the effects return, all you're using is the power amp section of that amp.
When the chorus pedal is engaged, you get a full chorus that's spread left and right.
As I said, there are numerous variations of this, but that's one way to do it. Running in stereo is very cool. If you have the gear, try it - you'll like it. It's a headache to set up, but once you get it down, it's great.