Hey there, I know this is late, but if you are talking about just the preview window for phones and pc (web browsers), then you must run Construct 2 as administrator and "Host" your preview. Choose the port on your pc that you want to host on (This is in File>Preferences>Preview) and you will need to give your local IP address to your friend. If you want to be able to test from anywhere, you will need to port forward, and give your external IP address with the port to someone. eg. 98.101.101.10