How do you get the backburner on tf2?

To get the Backburner in Team Fortress 2, you need to unlock it as a reward for playing the game. You can achieve this by either completing specific achievements related to the Pyro class, such as "Burn 10 enemy players with fire" or "Get 10 backstab kills." Alternatively, the Backburner can also be obtained through the in-game Mann Co. Store by purchasing it directly or through trading with other players. Once you meet the requirements, it will be added to your inventory.