-------------- INSTALL GAME -------------------

you need to install these:
apt-get install screen unzip libc6-i386 lib32stdc++6

install for 32bit: (Optional)
apt-get install libncurses5:i386

download the game:
wget https://polyfield.net/builds/Polyfield_X_Linux.zip

unzip the game:
unzip Polyfield_X_Linux.zip

give it execute permission:
chmod +x Polyfield_X_Linux.x86_64

---------------- GAME CONFIG ------------------

run the game once to create the folders:
./Polyfield_X_Linux.x86_64

close the game after 1 min:
Ctrl + C  or  Ctrl + Z

Place the config file here on your VPS:
cd /root/.config/unity3d/Mohammad Alizade/Polyfield/

download the config there:
wget https://polyfield.net/builds/ServerConfig.txt

edit the config:
nano ServerConfig.txt

save:
Ctrl + O
Enter

go back to root:
cd /root/

-------------- RUN SERVER --------------------

create a screen so you can close the terminal:
screen -S test

run the game in screen:
./Polyfield_X_Linux.x86_64

detach from screen:
Ctrl + A + D

close the terminal.

----------------- ENJOY ---------------------

later accessing the game:
screen -r test

see the running games:
top

close:
Ctrl + C

--------- Download some good maps ----------- (Optional)

move to the location:
cd /root/.config/unity3d/Mohammad Alizade/Polyfield/editor

remove all maps:
rm -r *

download back:
wget https://polyfield.net/builds/Server_Maps.zip

unzip:
unzip Server_Maps.zip

----------------- BAN-LIST ---------------------

users get banned for 14 days.

server saves the ban list here:
/root/.config/unity3d/Mohammad Alizade/Polyfield/banned-users.txt

close the game before editing.

------------------ CRONJOB ------------------ (Optional) (Restart app every night)

edit crontab:
crontab -e

restart every 6 hours:
0 */6 * * * pkill Polyfield ; ./Polyfield_X_Linux.x86_64 &

save:
Ctrl + O
Enter

------------------ SYSTEMD ----------------- (Optional) (This will keep the app running if crashed)

create file for auto-run service:
sudo nano /etc/systemd/system/game.service

copy & paste into the file:
###########################################
[Unit]
Description=Game Server
After=network.target

[Service]
ExecStart=/root/Polyfield_X_Linux.x86_64
Restart=always
RestartSec=5
WorkingDirectory=/root
User=root
RestartForceExitStatus=0
#Environment=GAME_VAR=value

[Install]
WantedBy=multi-user.target
###########################################

reload & start:
sudo systemctl daemon-reload
sudo systemctl enable game.service
sudo systemctl start game.service

check status:
sudo systemctl status game.service

see live logs:
sudo journalctl -u game.service -f