On my MacBook Pro, it isn’t necessary to click anything. If the pointer is hovering over a slider or a value, pressing the up arrow or down arrow key changes the value by a default increment that depends on the specific option. If you add the Shift key, the increment is larger, and if instead you add the Option key, the increment is smaller.
For example, when hovering the pointer over the Contrast slider or value, pressing the down arrow key decreases by 5 units, Shift + down arrow decreases by 10 units, Option + down arrow decreases by 1 unit.
For Temp the increments are 50 Kelvin, or 200 with Shift, or 5 with Option.
The arrow keys do the same thing if you did click in a value field.
This might work the same way in Windows, only because as with Photoshop, so much of the application is the same on both platforms.