So when I was first using this mod, it was much simpler, with the config only consisting of brightness, darkness and resolution. Now that colours and sun direction have been implemented, I found it much harder to setup. Here is how I managed to get the shadows working:

1. Mess with the colours - When colours were added, I didn't know how to use it so I set all of them to 0. DO NOT DO THIS, it disables shadows. What you need to do is raise the colors and keep them at the same valve (I set them to 110 - not too bright, not too dark)

2. Mess with brightness and darkness - You need to raise brightness and darkness to see the shadows. Try to get the brightness fairly bright, think of a cloudless sunny day. Then raise up until the darkness until shadows become fairly visible. After that, mess around until you're happy with it.

3. Fixing the sun direction - The creator decided to change the system (I don't know why) but it is really confusing since it no longer uses the map's provided sun. What you need to do is mess around with all 3 until you get the right shadow direction. This varies from map to map, so you'll have to change it for every map you play.

I hope this helped, it took me several hours to get this working but it works great once you fixed all the issues!