I have also this version, most of the things works fine, however I have problems with the scream, sometimes when I try to weak up the smart phone the scream became black and is impossible to use. The only possibility is take off the battery and restart the system.
it comes pre-rooted.
You need to open the "Security" app
Bottom Right --> Permissions
You will see "Root access"
There you can grant the apps that asked for root rights what they need.
or alternative - install supersu and grant supersu the right for root and use this one for granting root priviliges from now.
This way you can do it with a popup and dont need to close the app and go back to security center all the times.
To add on the list of advantages of using SuperSU over stock root app. Some apps simply won't work with the stock lbe binary, like Titanium Backup. Even though I prefer SuperSU over this stock lbe thing, I gave it a shot, but in the end had to flash SuperSU to get everything working properly.