What is needed for a VK application project?

Question

Project management

Project :
1. Private site - an application in the VK window for it, such a strange scheme was chosen due to corporate rules: you cannot create a separate public site and use it for commercial purposes.
2. VK application - gamification of interaction with users. Accordingly, one of the tasks of the application is to collect data for CRM.
3. There are approximately 300 employees who can be involved in beta testing (and the support of interested services is very high, so beta testing is not just words, I can, for example, make it mandatory to use the application for at least 10 minutes (arbitrary number of iterations) + completing the questionnaire (what can be added to it?) according to the results).
Problem

What milestones to introduce? (Offhand: interface prototype in presentation format, beta version, testing, launch). According to the programmer, everything can be done in 4 months.

Answer 1

humanitarian-PM - is it by diagnosis or by specialty?