You're right sorry. it's the 55 model and not the 50 that has the RGB controller.
I'm sorry I'm not too good with rgb/argb stuff and all the case models etc.
The only video I found about the fan connection is this one. I will let someone with more knowledge then me jump in this thread and help.
It shows two ways of plugging them. The first one at 1:09 and the second one right after. I think the first one is not using the RGB an the second one is. I might be wrong since it's in Japanese xD
View: https://www.youtube.com/watch?v=KVEFdBdEnlA