To collect payment from your Customers you need to Connect with us as a Merchant. To connect click the "Setup Payment" button.
After successfully connecting you will be able to Enable/Disable different types of payment methods you want to enable to collect payment from your Customers.
You can also enable Installments, which allows taking payment in Parts from your Customers.
To connect to PayPal you will need to signup for a Business account at https://www.paypal.com/merchantsignup/create and get your Client Id and Client Secret by following https://developer.paypal.com/docs/api-basics/manage-apps/.
After getting Client Id and Secret you need enter these here to enable PayPal.
You can take payments in parts from your Customer by configuring One Installment plan.