Code something only for admin ?

Here you go:

if (is_user_logged_in() && is_admin() ){
   // here do something for the logged in admin...
} elseif ( is_user_logged_in() ) {
   // here do something for everyone else who is logged in...
}

These are just a couple native WordPress functions you can use in your own code:

https://codex.www.ads-software.com/Function_Reference