Click the flag button, then choose either bag fight, or run, click one and for run, nothing will happen, fight will give you options, quick attack tackle ember and leer. Leer, will not do anything, while everything else will take HP off the following Rattata. Click bag, and the only option is potion, wich will heal Cyndaquil by 20 Hp. If your characters Hp drops to 0, or the opponents, the game ends.
Thanks to GameFreak, and Nintento in wich POkemon is owned by. Cyndaquil and Rattata are owned by Nintendo and their sprites are official in generation four games.