The Brush Tool lets you apply color adjustments to a specific area instead of the whole image. To do this:

1. Adjust one or more of the color settings on the left panel.

2. Click and drag on the image to apply the color adjustments.

To apply different color adjustments to another part of the image, click on New Selection.

Close this window when you've finished adjusting the selected area. Any further color adjustments will then be applied to the whole image.