Flutter Mobile App Development

We need a Flutter Mobile Development Expert, who can develop our mobile application.
20 app screens UI/graphics designs already finalized and our website working fine so need to develop a mobile application according our simple design and connect with existing website database
Hiring blue collar candidates App features: -
- Login / Sign In with OTP
- Profile update process
- Search candidates
- Show candidates profiles
- Show Job categories
- Show plan & Payment process
- Calling feature (call to candidates)
- Calling history
- Remaining credits in wallet for call to candidates
- Candidate resume & document upload
- Contact form (submit requirement)
- Create Ticket / Accept Ticket Events
- Ratings / Feedback
- Notification System
- Firebase Database
- Messages Integration /Chat

As above mentioned we have already done a main part of my idea so after the development need to explain us the complete code.