How to run PHP in nginx and fix the errors

first you gonna need to backup the conf file in order when you did something wrong, who knows tho?

and then edit them;
dunno wheres the config file located?
just run nginx -t and it will show you wheres the conf file and its content.
now just edit it with the following:

put root YOUR_INDEX_ROOT; at the top and inside of http { params
the purpose is to set it as global root directory.
and within location ~ \.php$ { edit with the following params:
try_files $uri =404; # try to find the file, if fail throw 404 error
            #root           /data/data/com.termux/files/home/sdcard/www; # this is the root dir of php files
            fastcgi_pass   unix:/data/data/com.termux/files/usr/var/run/php-fpm.sock; # pass every php file to this server
            fastcgi_index  index.php; # the index file name
            #fastcgi_split_path_info ^(.+\.php)(/.+)$; # ?
            fastcgi_param  SCRIPT_FILENAME  $document_root$fastcgi_script_name; # param for fastcgi to find the script
            include        /data/data/com.termux/files/home/sdcard/www/nginx/fastcgi_params;
        }

okay then save it and if everything's fine you can run php-fpm by just type php-fpm and hit enter in terminal.

note:
you can also set the fastcgi_pass value to a server addr.
but it seems that php-fpm always use socket file in the first place rather than a server addr.