On most laptops there is a Function Key (Fn) and holding this down with one of the function keys (F7 or F8 on mine) increases or decreases the brightness. The relevant function key will have a circular "light bulb" with a vertical arrow.
Surface Pro (2017) vs Surface Pro 4
20 groundbreaking 3D animation technologies coming to Siggraph 2017
iPad Pro 12.9 vs Surface Pro 5
Synology invites you to visit them at Insomnia on 26th – 29th August. Book your tickets now and visit Synology.