Start by plugging the USB cable into the USB port of your computer to connect the webcam. Wait for your computer to detect the new device. Once it has, a message will appear on your screen, telling you that your device is now ready to use. External webcams come with software that has to be installed on your computer. To do this, insert the disc that came with the webcam into the disc drive and follow the download instructions. The webcam should now be ready to use.