1) Download everything.exe
2) Search Javaw
3) Copy lunar client path (Right click on Javaw and select copy full name to clipboard.)
4) Use that as your path
5) ez
Example: C:\Users\Entropy\.lunarclient\jre\zulu8.50.0.53-ca-fx-jre8.0.275-win_x64\bin\javaw.exe set that as your javapath in settings.