If your currently on 4.4 kit kat stick to kit kat roms or use Odin to flash a lower official factory firmware. You'll access to a pc to install Odin software in order to flash the custom recover which is necessary in order to flash custom rom .zip. I would strongly advise not to immediately flash root or custom rom untill you first make a complete back up of all your participations. Save them to external sd and keep a copy saved elsewhere. I also advise waiting before flashing any modifications other than custom recovery. You'll get a much better reception if you wait until all your carrier data has been downloaded. Yes you'll get bloat but it will give your device much better network conectivity. As you don't want all the carrier bloatwear just pick a debloated custom rom.
