I am just starting to tinker with timeline, but I have seen this done by adding timeline as a plugin to the light that you want to adjust. When you add timeline as a plug in for that light, you can add triggers that change intensity, toggle on/off etc. The best way I have learned is looking at how others have leveraged timeline. NLVam does a number of complex actions with timeline, to include moving the lights and changing the intensity, you could look at how it was set up in these instances.