How to change button title "next" in to other languages

Hello, I have one website, and it is translated in to few languages, how to change button in signup page I mean button "next" , this button is in the bottom of signup page... I can change name of this button in file "Signup.php" this file is in folder amember\library\Am\Form\Singup.php and there is a function in this file

PHP:

public function __construct($id = 'signup', $wizard = true, $propagateId = false)
    {
        class_exists('Am_Form_Brick', true);
       
        Am_Di::getInstance()->hook->call(Am_Event::LOAD_BRICKS);
       
        parent::__construct($id, $wizard, $propagateId);
       
        $this->defaultPageConfig = array(
            'title' => ___('Next'),
            'back' => ___('Back'),
            'next' => ___('JOIN NOW!'),
        );
    }

but when I made a changes this button is the same on every signup page translated in few other languages..

how to make changes this button in to few other languages, and how to implement this ?

All text displayed in aMember should be editable at:

1. From Admin CP click on "Utilities"
2. Then Clik on "Edit Messages"
3. You can then search for "Next" in the search box at the top.
4. When you find the correct message you input the new message in the box to the right.

thanks..

ok I got it..