Trigger lights with timer

So i know how to make a light with this https://docs.unrealengine.com/latest/INT/Videos/PLZlv_N0_O1gZg3dTMetmsfm_s4lb4-Tg0/uJbfSWzfg7c/index.html
however im trying to make it so it slowly decreases to nothin with a set time. i e 30 from light to slowly darkness at 0.

Make a timeline. Inside the timeline set the length to whatever you want, and create a float track to go from 1 to 0 withing that length of time. Finally, use the timeline to drive a lerp to decrease and finally turn off the light.