How to Spectate in "TF2"by Seth Amery ; Updated September 22, 2017
"Team Fortress 2" ("TF2") is a cooperative and competitive multiplayer-only game where you join one team and fight against the other. However, you do not have to join a team and fight; you can spectate the match from a safe place. This lets you enjoy watching two teams fighting against one another without having to employ any skills in the game. Spectator mode features several cameras you can switch to at any time.
Click "Browse Games" on the main menu.
Double-click the server you want to join. Wait for the game to load.
Click "Continue" twice. You will see three doors and a television on-screen.
Click the television between the "Exit" and "BLU" doors. Alternatively, press "2" on your keyboard.
Left-click to cycle through the cameras. Right-click to go back to a previous camera. You cycle through static cameras and then through the views of each player. Press "Space" to change the camera view from first-person to third-person and to free roam.
If you are already on a team, press the period key (.) to change teams in-game.