I am trying to build my app but it failed. I am shown the message below.
error: WatchKit Extension doesn\'t contain any WatchKit apps whose bundle ide
So, you don't necessarily change something when you just want to run on test devices. But you do need to request two more provisioning profile in order to test the watch app. Those two additional identifiers can be acquired from extension target and watch app target. That's also the same things you need to do when you want to upload the watch app to App Store