Actually, now I’m more confused about what your issue is. 
On your 2nd screenshot, it seems that you already have 2 devices synced on your sync chain.
Did you want to add other device to your sync chain?
@Ran23 this 
You can’t see the button because you already have sync setup on your devices. You’ll see the button on your other device/s that you want to sync. See screenshots below
Android
Desktop
