Since the game is in an early alpha stage, please don't wait for a random group to form. Lobbies in this stage of the game usually don't stay for a long time to wait for other players. If you want to try the multiplayer capabilities, ask some friends to try the game with you.
Mini Tank Battles is in a very early alpha stage. A lot of functions, graphics, and audio are missing or contain bugs. The game has also not been balanced for difficulty.