How do i pay for this?
Fill out the form from the first post and make sure to use an email address that's connected to your PayPal account. Once your order is processed, you will be invoiced on PayPal (you will receive an email from PP and senter). Pay the invoiced amount via PayPal. That's it. It will provide you with 6 months of buyer protection.
Also, once your keyboard kit is ready to ship, you will be invoiced once more to cover the shipping costs. These will vary based on the weight and size of your order and the destination, but senter said it should be around $40.