1st thing is if your going to do this instead of the electrician, VERIFY that power is off in the switch box. Don’t think you can do it HOT because the electrician did. It only takes a split second and things can go bad. Better to be SAFE.
Well this is how Aeotec says to wire it.
You could just wire in the light portion 1st, then verify you have it working through smartthings.
NOTE: Make sure you have the line and load wires on the right screws. It makes a difference. Load wires (light) go on the outside screws.
After that you can add the 2 switch wires and verify again.
NOTE. the switch connections are fragile and will not readily accept say a 12 gauge connection. You will have to use a smaller gauge pigtail from the switch and wire nut it to your house wiring. There is NO POWER running through the switch so it is okay. Your just using the wiring as a loop to signal the micro the switch was toggled.
If this is how you wired it already, then I would check your connections. It does work when it is wired right.
If you get frustrated, already burned up your micro by wiring it wrong, or just give up there are lots of choices for you to use a smart switch vice a micro.