******************************************/
// Test if a user is logged in
if ($FEUP->Is_Logged_In()) {
    // Display the menu named "Logged In Menu" if they are (created under "Appearances" -> "Menus" of the WordPress Admin)
    wp_nav_menu(array('menu' => 'Logged In Menu'));
} else {
    // Display the menu named "Logged Out Menu" if they aren't
    wp_nav_menu(array('menu' => 'Logged Out Menu'));
}
/******************************************
* DISPLAY POST BASED ON A USER'S INTERESTS
******************************************/
// Get the field value for the "Interests" field
$Interests_String = $FEUP->Get_Field_Value("Interests");
// Turn the string containing a user's interests into an array
$Interests = explode(",", $Interests_String);
// Check if lighting is in the array, and display posts in the "Lighting" category if it is
if (in_array("Lighting", $Interests)) {
    // this user is interested in lighting, display the lighting posts category here
}
/*****************************************
* THE FOUR HELPER FUNCTIONS
*****************************************/
// Retrieve the user's ID
$User_ID = $FEUP->Get_User_ID();
// Retrieve the user's username
$Username = $FEUP->Get_Username();
// Retrieve the user's username in a different way
$Same_Username = $FEUP->Get_User_Name_For_ID($User_ID);
// Retrieve the value for the field named "Interests", for the user with ID equal to $User_ID
$Field_Value = $FEUP->Get_Field_Value_For_ID("Interests", $User_ID);