orange pi r1 plus uart1

microdoc

I have a r1 plus and looking to use uart1 on the 13 pin header as a com port, how do I enable it..I see ttyS1 and ttyS2, I have tied minicom with tx and rx looped on ttyS1 and get nothing.. ttyS2 is access denied. I am using Debian.  Any help would be appreciated.
Thank you