It is important to follow the instructions in the documentation of your particular camera but, in general, the software and hardware installation of a web camera go hand in hand. The first step of the Logitech Quickcam Express installation is to insert the driver and software CD that shipped with the product. This CD takes you through the driver installation as well as application installation in one hit, and at the completion of the process will ask you to shut down your system so that you may plug in the webcam. Some other camera installations will even tell you when to plug in the camera, and you may not need to restart. Otherwise - and in this case - upon restarting your system, it will detect your camera. Indeed, plugging in the camera and associated peripherals (such as a pair of headphones or speakers and a microphone) is as tough as the hardware installation gets.
Once the system is restarted, go the Device Manager to make sure that the camera has been installed successfully. If there is no yellow exclamation mark next to it, then your installation went according to plan; if there is a yellow exclamation mark next to it, then you will need to attempt the driver installation again. Failing that, check out the troubleshooting section of your documentation and visit the vendor's Web site for more advice.
From the Start menu, navigate to the Logitech QuickCam Express folder and launch the QuickCam Express program. This will immediately set off the audio and video wizards that will guide you through the program's configuration. (These can also be run at any time by clicking on the audio and video icons from the program's toolbar.)