Relay with PixHawk

Good morning all,
I am currently working on a surface drone project. I use the PixHawk 4 as a flight controller. I want to control a 12V lamp that I will activate or not this lamp. For this, I tried to control it simply with the light function but since this one works in 5V I was not able to use these functions.
So I turned to the use of a relay but I can not control this relay with the existing function.
I want to control the output like a GPIO to turn my 5V relay on or off.
If anyone knows how I can go about it that would be wonderful.
Thanks everyone.

Good morning all,
nobody have an answer for me ??


thanks @terrymao886 !
I have 5V between my Ground and my β€œ+” on my AUX5 and when i put my relay β€œon” on QGroundControl i have 3.28V between the Ground and my signal.
Do you think with your link my problem would be cleared ?
Thanks a lot !