What is the make/model of your laptop and what operating system are you using?
First is to look at your keyboard. All of your keys will have your main characters assigned to each key in bold, white letters, but some may have other characters or symbols in a different color.
This is a good example from a Dell keyboard where you have the volume keys above the numbers 7, 8, and 9 on the very top row (mute/volume down/volume up respectively). It's easy to see taht you simply hit these keys to mute, lower or raise your volume...very straight forward.
You also see that this keyboard has some smaller blue characters on the top row, set as the Function Keys. To access these you first hold the "Fn" key on the very bottom left of the keyboard (between Ctrl and the Windows key) and then press the top row to access the related function. I only point this out as some laptops have the Volume Up/Down set as such, where you will have to hold down and alternate key first (usually the same color) and then press or hold down that second key to activate it.