In the user table how coul'd I make the main admin, I don't find any info on this first users... I tried Auth::create_user('admin', 'password',...) and I got Parse error - Invalid method...
No, if you run 'refine migrate --all' or 'refine migrate --packages=auth' oil will run those migrations.
Before you do, make sure you have configured auth (i.e. copied config/auth.php from the package to your app/config, and configured you want to use Ormauth), otherwise the correct tables will not be created.