Find a photo you think might look good in black and white. Good contrast, a wide range of value.
Image > Image Adjustments > Black and White.
The sliders adjust the light and darkness of different colors in the photo. So if a slider doesn’t work well, that just means your photo doesn’t have much of that color in it.
For best results, Image > Adjustments > Levels and bring the triangles to the beginning and end of the mountains.
In Lightroom, click Black and white for your treatment over on the right.
Then open the B&W controls and you will find similar sliders to adjust the brightness of colors in the original photograph.
In Lightroom you can drag the histogram so the darks are all the way dark and the lights are all the way light.
Create a few black and whites and post your favorite on the forum. If you have a photo with good value, post it to the value forum.