Rooting any device is specific to the device. DO NOT use root methods for other devices. It is very hard to hard brick a phone these days, but it can happen. You may wipe the boot partition and then have massive trouble writing it back without access to the recovery.
Rooting allows you 'Root Access' permissions over the Linux base of the phones boot and recovery. Access to write control of these partitions is usually held by the manufacturer. We have laws that allow us to modify these areas after the phone becomes our property. Gaining root for different devices is done in many different ways. Some manufacturers allow you access if you give up warranty. Some are accessed through a back door in the OS, usually the camera application because it's big and full of holes. ONce you gain root permissions, you can use or install a new recovery. You use recovery to make copies of your nand memory like the OS, boots, etc., and flash new OS, recoveries, etc. You can also gain root access and change nothing. Most people attain root access to simply be able to install a tether application.
XDA is full of information. READ IT ALL BEFORE YOU DO ANYTHING