[COLOR=darkorange]1.[/COLOR] From the starting screen, click Options, then Mouse/Keyboard, and enable the [B]developer console.[/B]
[COLOR=darkorange]2.[/COLOR] Start a single player game and open your console with the ~ key.
[COLOR=darkorange]3.[/COLOR] Type [B]"sv_cheats 1"[/B] and press enter. This will enable cheat mode.
[COLOR=darkorange]4.[/COLOR] Type [B]"ent_fire !self setteam 3"[/B] and press enter. When you close the console, you will "die" and join the Infected team!
You get to choose where to spawn as a baddie! [B]Press E to cycle through some suggested spawn locations, or to teleport
directly to the survivors if you get too far away before spawning.[/B] But the next problem is that the AI controlled survivors
will not leave their starting room and the game will not start on its own.
[COLOR=darkorange]5.[/COLOR] Open the console and type [B]"director_force_versus_start 1"[/B] and enter to begin the round.
The survivors will start hacking their way through the apartment building and you finally get to try your zombie character!
[COLOR=darkorange]6.[/COLOR] When you die (and you probably will), you will not respawn. [B]Press space to cycle through different spectating modes
till you are in in free flight mode.[/B] You must then use these commands in the console WHILE DEAD.
[B]z_spawn tank
z_spawn boomer
z_spawn smoker
z_spawn hunter[/B]
These will spawn you as that infected at the spot you are currently "flying" while dead.
[COLOR=darkorange][B]The Subways[/B][/COLOR]
Substitute the "force_versus" command with [COLOR=darkorange][B]sb_all_bot_team 1[/B][/COLOR] to make the Subways playable with a bot team.