Hi Ayesha,
Go ahead and uninstall ffdshow when prompted to do. So when it says:
Setup has detected that you have ffdshow installed on your computer.
The K-Lite Codec Pack [full version] also contains ffdshow, It is recommended to uninstall your current version of ffdshow.
Would you like to uninstall ffdshow?Select - Yes
Just make sure when you go to 'Advanced Install' as described in your video link ,you leave everything as it is so it will install ffdshow again and also tick the box selection:
ACM audio codecs to get those codecs. Restart your computer when prompted to do so.
I've tried this already, and it didn't affect LR or LM.
Hope this helps!