PHPasap provides the Session library to handle native session. By default sessions are already started. So you don't have to do a session_start()

Set new or update existing session variable

Instead of using the global $_SESSION directly you are better off with below code

Session::set("name", "value");
Session::set("name", ["value_1","value_2"]);

Get session variable value

Similarly for getting a session variable value you can use below code

$value = Session::get("name");
//returns null if "name" wasn't set

If given session variable not found then get() returns null.

Flashing data

Flashing a session means the session variable will be available only for next request. This is particularly useful for showing form validation error.

Session::flash("error", "Username/Password incorrect");

Retrieving the flash data

Getting the flash data is same as getting any other session variable

$error = Session::get("error");