To set up your printer via 123 hp com setup, ensure it's powered on and connected to your network. Visit 123 hp com setup on your web browser. Enter your printer model and follow the on-screen instructions to download the necessary software. Run the downloaded file to install the printer drivers and software. Once installed, complete the setup by following the prompts, including connecting the printer to your network. Finally, test print to ensure successful setup via 123 hp com setup.