Integrating WWF in asp.net MVC application

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ASP.NET

MVC

WF

WWF

MVC4

workflow

I have one asp.net MVC based application for vendor data collection system.

Vendor will be provided with 1 temporary generated link, username and password. Vendor visits the link and fills the form (Asp.net MVC based).
As soon as vendor fills the form data should be visible to person1 (lets say P1). P1 either approves or reject the entry. If approves it goes to person2 (lets say P2). P2 also either approves or reject the entry. If approves it goes to person3 (lets say P3).

All P1, P2 and P3 has their windows authentication based web application to see all data, vendors entries, vendor request status etc. All that has to be developed in asp.net MVC site.

For above mentioned scenario how can I achieve interaction with my WWF from my MVC based web app.?

When I google it I found multiple places that It is recommended that we should achieve this using service calls. But I didn't find any proper tutorial or steps to follow.

Please guide me step by step and from beginning as I am a fresher In WWF. Project structure, implementation everything guidance is required.