How do you use devmap command on CoD 4 Modern Warfare on PC?

To use the devmap command in Call of Duty 4: Modern Warfare on PC, you first need to enable the console by going to the game settings and ensuring it's activated. Once in-game, press the tilde key (~) to open the console. Then, type devmap [mapname] (e.g., devmap mp_crash) to load the specified map with developer mode enabled, allowing you to use cheats and access additional features.