Using your Canon EOS 7D DSLR camera body is easy. First, insert the battery into the battery compartment. Then, power on the camera and start exploring different shooting modes. When shooting, hold the camera steady and use the viewfinder or LCD screen to frame your shot. For better results, try different settings according to the lighting and the subject. As for maintenance, keep the camera dry and clean. Use a soft, dry cloth to wipe the body and lens regularly. Avoid exposing the camera to extreme temperatures or humidity. When not in use, store it in a protective case. And remember, always update the firmware to the latest version to ensure optimal performance.