for phpMyAdmin-4.8.5-all-languages copy content from config.sample.inc.php into new file config.inc.php and instead of
/* Authentication type */
$cfg['Servers'][$i]['auth_type'] = 'cookie';
/* Server parameters */
$cfg['Servers'][$i]['host'] = 'localhost';
$cfg['Servers'][$i]['compress'] = false;
$cfg['Servers'][$i]['AllowNoPassword'] = false;
put the folowing content:
/* Authentication type */
$cfg['Servers'][$i]['auth_type'] = 'config';
/* Server parameters */
$cfg['Servers'][$i]['host'] = 'localhost}';
$cfg['Servers'][$i]['user'] = '{your root mysql username';
$cfg['Servers'][$i]['password'] = '{your pasword for root user to login into mysql}';
$cfg['Servers'][$i]['extension'] = 'mysqli';
$cfg['Servers'][$i]['compress'] = false;
$cfg['Servers'][$i]['AllowNoPassword'] = true;
the rest remain commented an un-changed...