Quiz App for Android - UI/Graphics Needed too!

I need a small and private project done.

Concept:
User opens the the app - press "Start" - User can then select to "Practice" and selects which Category he/she would like to practice. The user will be shown a percentage of how many correct answers they have made.


We want the same concept/design but obviously with our own categories and questions. The backened needs to be done where the admin can change/add questions or categories and also the design/UI. I've made a sketch of what I want it to look like. A minimalist design will do!