Sometimes shown as just “M”, Manual mode lets you choose both the shutter speed and aperture, giving you full control of the exposure. However, you will also need to learn to use the light meter. This is no big deal and actually gives you even more control. Typically the light meter appears in the viewfinder (or LCD panel) as something like “+ . . 0 . . - ”. Note that in some cases the display is reversed, i.e., the “+” is on the right and the “-” is on the left. You may even be able to control how this is displayed using your custom settings.
If the image is overexposed (i.e., too much light is entering the camera), it will look something like “+ ||| 0 . . - ”, in which case you need to adjust the exposure to use one or more of a slower shutter speed, smaller aperture, or lower ISO to ensure a “good” exposure.
If the image is underexposed, it will look something like “+. . 0 ||| -”, in which case you need adjust the exposure to use one or more of a faster shutter speed, larger aperture, or higher ISO to ensure a “good” exposure.