use \MyUser\MyUserPay;
include 'MyUserPay/init.php'; //path/to/MyUserPay library
MyUserPay::setPrivateKey('Your Private API KEY');


$process = MyUserPay::charge(
array(
//Charge $100
'amount'=>10000,
//If request was post
'token'=>$_POST['MyUserToken'],
)
);
if($process['status']){
//success
$charge_id = $process['id'];
}else{
//error
echo $process['error']['message'];
}

<form action="charge.php" method="post">
    <script 
        src="https://api.myuser.com/js/checkout.js" 
        class="myuserPay-button" 
        data-public_key="Your Public Key"
        data-amount="10000"
        data-description="Description of item"
        data-name="Your business name" 
        data-image="Your logo url"
        data-submit-ajax="0">
    </script>
</form>