Yep, i found the correct answer :
If you still don’t have a PayPal account, you can create one by pressing the Sign Up Now button on the top. After that, you should return to the PayPal extension screen and enter the email address that you signed up with. You can change the settings to suit your needs and even customize your checkout page. You should also make some test transactions and see if everything is how you want it to be by setting the Status of the extension to ON while you are still in Sandbox Mode. And when you are confident that everything is alright, just remove the Sandbox Mode from the dropdown menu and Save. You should see the PayPal Sandbox text disappear from the background and be sure that you can accept payments securely to your PayPal account.