You have to create fully working app, not just empy placeholder. This requires coding in Android Studio. Its the similiar thing just vice-versa as with Facer watch faces which are currently hugely promoted on Google Play. You can buy some Facer watch face just to find out that you also need their phone app.
This is the same that is required for some Facer and Watchmaker watch faces on the Galaxy Store. Facer runs (for the lack of a better word) an emulator on the Watch that is controlled by the companion app on the mobile. Facer also allows native watch faces without a controller.
Since Facer is an aggregate seller that gives them an advantage in social media marketing.
Ron
Samsung Developer Relations