Hi,
Yes you can. Connect to your device from the main IDE using Tools /B4A Bridge/Wireless or Bluetooth (or via USB). Then in Designer double click on Connect & you should see the design on your device.
If the emulator is running you will be offered a choice between the two.
I've been playing around with the BlueStacks App Player, & noticed that it is also offered as an emulator from the Design screen - quite useful
Regards,
Robert