A mouse is a popular peripheral for a computer. It usually connects to your computer via a USB connection or an adapter for PS/2. If using the mini DIN PS/2 connector, it is generally green colored on the back of your computer. Your mouse may be wireless, which means you’d probably have a wireless connection through USB.
Modern mice are optical devices with few moving parts. There’s a light underneath the mouse that determines if the mouse if moving. You may need to find the right surface in order for your mouse to function properly. For example, glass surfaces may be an issue for an optical mouse.