The "best way to root" will depend on what you want to accomplish by rooting. You can root the phone simply to use apps that require root permissions or to run certain apps such as Adaway.
Many people like myself are running ROMs that have many other features installed that the stock ROM for their phone doesn't contain already.
On my Note 5, I am running a ROM that has greatly improved the battery life simply because without it, my Note 5 was unusable.
You should head over to the XDA forums and read up about how to root your Note 5 (if your carrier version allows root).
It's far too difficult for anyone here to simply tell you the best way to root. Just be aware that you if you install the wrong ROM or do something else wrong, you can prevent your phone from being able to even boot up. You can always fix it but you will need to know how and for many, you may not know how.