There is a DIY somewhere that I used, I will try to find it, but basically you need to remove the 2 little covers off the paddles that cover up the electronic board and then you need to press you the shaft that the paddle pivots on (be careful when you get it all the way out and can remove the paddle as there is a small spring and ball under it that can pop out. Once you have the paddle out, you wil then be able to unscrew it from the rest of the assembly and attach the new one and reassemble.
I will see if I can find the DIY I found that showed it
2008 E93 335i, GIAC Stage 2, HPF IC, Injen Intake, Defective AR Design DP's with useless cats
2014 X3 35i JB Stage 1