Creating a group is simple. In the main screen of the WiZ application, long press on any light, within a room, and drag it onto another light of the same room. The two lights will now appear in a single circle: you have created a group.

Note: There may be a slight delay between the moment you release the light on the other and the moment the group appears, if your Internet connectivity has some latency.

Note 2:
You can only group lights of the same type: Color lights together and Tunable White lights together. Mixed groups cannot be created.