UI and API Integration for Windows C++ App

I need modifications on a Windows application built with C++. The app's source code is available.

Key Tasks:
- UI Modifications:
- Improve layout/design
- Modify existing UI elements
- Design files are available for reference

- API Integrations:
- Data retrieval
- Authentication

Ideal Skills:
- Proficiency in C++
- Experience with Windows application development
- Strong UI/UX design skills
- Familiarity with API integration, particularly for data retrieval and authentication

Please provide examples of similar work done.