Connect Arduino UNO WiFi with Android Studio app


So I'am working on my final School Project before finishing school, and I decided to make a robot, which I will drive with my Android phone on WiFi connection. I've built my robot, and tried basic stuff like driving forward, spin right, etc... I've also created my Android app where I have 4 buttons (forward, backward, left and right). My problem now is, that I could not find any source of how can I connect my Arduino program that is running on Arduino UNO WIFI Rev2 with my Android Studio app.