@Skidwai I don't have a HS200, the Smart Actions should be able to do that.

@NightHawkIX A neutral is never connected to a dumb switch. If you have two light fixtures connected to the switch then the two blacks are the common/load, and the white is power/line. Else the two...

@Barok77 The two wires on the same contact tells me there is more then one fixture. Put the single black to the Line of the HS200 and the two black to the load of the HS200. You should have three...

@SeanGotGjally The two switch operation tells me this is a 3way switch. You need to use a HS210 for 3way switch replacement. Also a picture of the wiring on both sides of the switch before the change...

@Techbuzzard The red and white on the switch are travelers. The whites under the wire nut in the box is the neutral.

@Engineer_Dan From the wiring description of the dumb switch, that is a 3way switch. You need to use the HS210 to replace it.