Help a beginner who is about to install cyanogenmod 13 on a samsung Galaxy Note 10.1 2014 edition I have a Samsung Galaxy note 10.1 2014 edition that is my love. It is my daily driver too. I recently upgraded to lollipop, but faced issues with graphics quality being dropped due to some memory leaks or whatever (maybe it was developers making excuses cos they can't do anything) 

I can't play games nicely cos the graphics are terrible. Samsung released an app called Game tuner, but it is only for the s6 and above. (Thank you for abandoning us Samsung). I decided to flash twrp recovery and CyanogenMod 13, so I could side load that app and the service it requires to run (the service is restricted to marshmallow)

According to their website, I can use Heimdall suite to do the flashing. I would love a guide please, step by step. They mentioned that you don't need to root in order to flash custom ROMs. Is this true? 

But yeah, this is a $700 device when I bought it couple of years ago...warranty is expired. And I don't want to mess up this. 
Thanks!

Edit: My device is the Sm-P605 and the nightly release for my device has code: lt03lte

I know there are risks involved and want to minimise them. I would prefer not to root but just flash twrp recovery and CyanogenMod 13.
FIRST in twrp go to BACKUP and backup your device so if anything goes wrong you can RESTORE and start over. 

its very simple copy the cyanogenmod .zip to your sd card. then boot into twrp and goto wipe and select advanced wipe and and delete system,data and boot. dont delete recovery or sd card. then go to the main twrp screen select install and locate the cyanogenmod .zip and flash away. you well also want the google apps knows as Gapps. i recommend flashing them after cyanogenmod then once both are flashed do a factory reset in twrp, i know sounds dumb but gapps has issues and if you dont factory reset you will get a Play services has stopped message that will spam you screen and or a startup wizard had failed. any questions shoot me a message or reply.