To issue any command, simply press the tilde (`) and type away. Since some of these can crash the game instantly, tread carefully. For running purposes, using the engine commands or issuing a Python command to alter the game's story state or DnD based rules should only be done for testing purposes. Commands can be simple setting changes (console variables, or convars, ie turning off rain effects, disabling player bob), engine commands (loading a map, starting a benchmark, etc), or game rule changes (which are Python based). The console is a basic text parser that allows commands to be run and settings to be changed without having to load up the game's (very limited) menu system. Click OK, and the console will be fully enabled everytime the game is loaded. Next, click on Set Launch Options, and add in -console on the next popup.

Under Steam's Library tab, right click on Vampire: The Masquerade - Bloodlines, and click Properties on the dialog box. The console should appear when you start the game, and can be accessed using the tilde (~) key. Append -console to the end of the target, outside of the quotes (ie, 'wherever you have this folder installed\Vampire - Bloodlines\vampire.exe' -console). Right click the desktop shortcut and go into properties.