if you are using nginx, i suggest you download the file from https://www.phpmyadmin.net/downloads/ and extract it anywhere you want.
after that just make a configuration on your nginx (the default is /etc/nginx/sites-enable/default), something like:
server {
listen 80; ## listen for ipv4
server_name phpmyadmin.x; ##change it as you wish
root /var/www/sites/phpmyadmin; ##path to your phpmyadmin directory
index index.php;
location ~ \.php$ {
try_files $uri =404;
fastcgi_pass unix:/var/run/php5-fpm.sock; ##just adjust with php7 version
fastcgi_index index.php;
fastcgi_param SCRIPT_FILENAME /var/www$fastcgi_script_name;
include fastcgi_params;
fastcgi_read_timeout 300;
}
# deny access to .htaccess files, if Apache's document root
# concurs with nginx's one
#
location ~ /\.ht {
deny all;
}
}
then edit your /etc/hosts and add phpmyadmin.x (change it if you want) on 127.0.0.1
restart your nginx. (service nginx restart)
make sure you already install php7 lib for mysql. maybe php7-mysql or something like that. and then restart the php-fpm