The External IP Address is assigned by your ISP to your router which in turn assigns different Internal IP Addresses to all devices in the network. The outside world can only see your external IP address. In short it cannot distinguish between your dad's computer and yours.

When a Server sends you some data, it will be transmitted only to your device by your router(because you requested it) and not your dad's.  (please correct me if i'm wrong)

The external IP address is assigned by your ISP to your router which in turn assigns different internal IP addresses to all devices in the network. The outside world can only see your external IP address. In short, it cannot distinguish between your dad's computer and yours.

When a server sends you some data, it will be transmitted only to your device by your router  (because you requested it) and not your dad's.  (Please correct me if I'm wrong.)

Your router assigns different internal IP Addresses to all devices in the network.

The External IP Address is assigned by your ISP to your router which in turn assigns different Internal IP Addresses to all devices in the network. The outside world can only see your external IP address. In short it cannot distinguish between your dad's computer and yours.

When a Server sends you some data, it will be transmitted only to your device by your router(because you requested it) and not your dad's. (please correct me if i'm wrong)