I’m adding a new exhaust fan to my bathroom where there was not one before. I added a double gang box for a second single-pole switch to operate the fan. The existing light switch had the following: a red and white wire coming into box, the red was hot and was connected to switch for light; a black and white coming into box, the black was not hot and was connected to other screw on light switch.
What I did was add pigtails to the “hot” red wire, and connected them to each respective switch; the light and the new fan. I connected all the whites together and the grounds together. I’ve provided a picture below. All appears to work well, but because I am not professional, I always like feedback for piece of mind. Thanks!