Once the camera is set to manual, you can use the control wheels or dials to change the settings. If your camera has two wheels like this one, one will change the aperture (shown as an “f” stop) and the other will change the shutter speed.
If you only have one dial...
If the camera only has one dial, like this camera, you will usually need to hold this button while you rotate the wheel to change the aperture.
Change your ISO.
To change ISO, there is typically an ISO button. If not, it can normally be found in the camera’s menu.
Use the exposure meter to get a 'correct exposure'.
Adjust the settings so that the exposure meter in the viewfinder lines up in the middle. This will give you a correct exposure.
Experiment with changing different settings to discover the way they change the look of your photos. Remember that as you change one setting, you’ll need to change one or both of the other settings to get a correct exposure.