Thanks this solved my first problem, then I tried to log in with root and no password I got this error "login without a password is forbidden by configuration"
So I went to the setup page "Basic settings" tab, 'http://dcerouter/phpmyadmin/setup/index.php
" and I created a config directory in "/var/www/phpmyadmin/config" and enabled read/write access per instructions, then I created default server to point to localhost with "tcp" connection , "mysqli" PHP extension, "cookie" Authentication type, "root" user for config auth, "blank" password for config auth, "checked box" connect without password, "blank" swekey config file.
Also I modified "server configuration" tab and I "checked box " Allow logins without a password
And I get the same error message when I log in as "root" with "blank" password