This is a game called Tic Tac Toe it has two modes singleplayer and multiplayer, So you can play with another player and also with the computer too.
In the singleplayer mode you have to enter your name and then randomly computer or you will get the first turn, you will have 'X' as your symbol and 'O' will be computer's symbol. In the multiplayer mode you have to enter your names and then randomly one of the player will get the first turn, one player has 'X' as his symbol and another player has 'O' as his symbol.
In this game you have to press a number to play your turn corresponding to the position of the block where you want to place your symbol. It accepts numbers from 1 to 9 as it has 9 positions and it won't accept a number if there is already a symbol on that position.
Singleplayer mode also have two types of levels to choose one is easy and another is standard. Easy mode has a beginner bot playing against you and in the standard level you will play against an expert bot. When the match will be ended either by wining or by a tie after that the game will give you two options that if you want to play again or you want to exit. Then you can enter '0' if you want to exit and '1' if you want to play again.