Help S5 android lolipop 5.0 UNOFFICIAL

[Android Question]

Hey guys, so I have a galaxy s5 SM-G900f wich I installed on an unofficial lolipop 5.0 version back when it wasn't given to everyone which means I can't really get official updates.
I want to install the official lolipop on my phone so that I can get the updates and everything, any idea how to do so ?

 

[Slug]

This thread, in the Galaxy S5 sub-forum, should tell you all you need to know.