Hi Alex,
Once installed, FSLab Spotlights loads automatically for each aircraft where there is a FSLSpotlights.ini file. The attached image is an example of what the E175 folder should look like once you've installed / copied the FSLSpotlights.ini file there. In the sim, you can verify it's installed by select the Addons menu and look for the entry for FSLabs Spotlights. If that's not there, it's not installed on your computer. If it's there, select it and make sure it is not Disabled.
Now, once you've loaded the eJet, the controls for FSL Spotlights might be a bit hard to find at first, but it is normally in the lower left corner of the screen. It's a semi-transparent window, minimized. You can click on the caret (looks like a small "v") to expand the window. It's resizeable using the handle on the lower right of the FSL Spotlights control window. Once you expand it, you'll see the different groups I've programmed; Chart/Overhead, Flood/Storm - Captain, Flood/Storm - FO, and Dome. These can be turned off an on individually by clicking on the green dash/check mark.
Also:
This does address lighting day and night.
You can adjust the brightness by editing the spotlight. You need to do that with the FSL Spotlights Manager. There's an editor there. That said, the colors and brightness, I tried to match from videos and photos I saw of the real EJet cockpit. The Dome is an incandescent color and fills the cockpit with light from behind. The floods range from blue-white to white, so if it feels too bright, you may want to adjust them. Also, check your HDR, Brightness, Saturation and Bloom settings in Prepar3D.cfg [GRAPHICS] section. That makes a difference. For my config;
HDR=1
HDR_BRIGHTNESS=1.100000
HDR_SATURATION=1.000000
HDR_BLOOM_THRESHOLD=3.000000
HDR_BLOOM_MAGNITUDE=0.200000
Hope this helps.
Jeffrey S. Bryner