Download the latest netbeans for linux from http://www.netbeans.com you will get .sh file

then save it in your Desktop

Before we can install netbeans, its requires the JDK (Java Development Kit) 

to install JDK from the terminal using the command

sudo add-apt-repository ppa:webupd8team/java

sudo apt-get update

sudo apt-get install oracle-java7-installer

after JDK installed completely, now we can install netbeans

just navigate to the location that save the .sh file

assume that the location is in Desktop

use the command

cd ~/Desktop

then 

sudo sh netbeans-7.1.1-ml-linux.sh 

The process will coming with the GUI now follow the instruction untill finished