Flutter app

I need set up and installation of this code canyon app:This is the full app plus backend:

https://codecanyon.net/item/eshop-flutter-ecommerce-full-app/29880351

? Need all my branding.
?I need link to my social networking pages :- to
     my YouTube, Instagram and Facebook page within
     the app.
? I also need a lay-buy payment put in ( this is when
     a customer can make payment an installment or
     deposits until they finish payment.

Payment Gateway
? The payment gateway will need deep linking.
       Payment gateway name is Payfast.

https://developers.payfast.co.za/docs

I need someone to set-up and reskin the app for me along with the things I mentioned.