How do I use the access arguments?
in this case, the first letter is "a" because the access argument is "administer create". If I remove administer the first letter will be "c" from &amp;create". And all fields from user entity get this letter as content :

name : "a"
tel : "a"
mail : "a",
etc.

Actually I just want to know how to say "if you are admin you can add content, if not, you can't". The best way is to use "Session authentication" or "Basic authentication" or "oAuth" ?? Don't know...