Build Distance Calculator App for salesman's

The app basically calculates the kilo-meter that which salesman travels during a particular session.

App Flow :
1. login/signup
2. start session ( with 0 km)
3. app continuously after every 3 or 5-second updates the current distance (in km)
4. end session
5. The user can see and download pdf the report from the start to the end date.
6. One admin login that can see all user lists, particular user reports, and current session details.

following API will be given :
1. sign up/login/update user
2. start session (0km)
3. update session
4. report (start date to end date)
5. admin API ( see all users, particular user report, particular user current session)