Remove/Add nvidia drivers ubuntu 14.04.2

I'm following Ubuntu Wiki to install the drivers for hybrid-graphics in Ubuntu 14.04.2.

Here are the steps:

NVIDIA systems:

1. Make sure that no other NVIDIA driver is installed (keep the
   nvidia-common package).


2. Install nvidia-331.



3. Reboot the system (restarting X won't be enough).

   
   
   

   NOTE: you can easily switch between GPUs from the Prime section of the nvidia-settings panel.

I'm not sure about step 1 - is it ok to just go to Additional Drivers and select nvidia-331 , will this uninstall other nvidia drivers if I have any ? And I guess this should install the driver (step 2) , or I have to do something explicitly like install from command line ?