There are many ways to create a BW image in Photoshop from an original color image.
One way is to use Adjustments.
First, open your image in Photoshop.
Next, pay attention to the bottom of the Layers panel where there is a line of icons and select the icon that is circular with half of it filled in white.
Towards the middle of the menu, there is a “Black & White” option. Click on that.
A new dialog box will open which contain many color sliders to pick from. By working with these color sliders, you have precise control over which aspects of your black and white image will become lighter or darker.