I would install mate on orange pi pc more starting from the server version.
someone tell me step by step how to do.
Thank you.

This is long process. I can help you with everything, except installing Mate environment. I guess this will be easy if you reach there. But Mate is not good for AllWinners boards (and similar), because composite-manager doesn't support GL ES2.0 and will be slow. You can check this - Ubuntu 16.04 LTS - MATE Desktop - Mali and vdpau drivers. Better stick to xfce in Armbian Desktop, or try LXDE.

Instead of doing everything from scratch, you can download Desktop Armbian image and remove xfce, downgrading it to CLI, then try to install Mate environment. If documentation is still up-to-date, this is how it have to be done:

sudo apt-get remove libxfce4util-common
sudo apt-get autoremove
sudo reboot

But you have to try, because i have some memories, in latest Armbian this will remove more packages than needed. Still better than doing from CLI.