Android app help please

Question

I am almost done making my android app....its a math app for my high school but there is this feature I want to add to make the app more exciting which is to enable users to challenge one another in maths...similar to the play feature in sololearn.. the problem is I don't know where to start. ....so if u have any idea please help....thank you very much. ..

Answer 1

I will do so thanks very much