A command console should appear when you press the `/~ key (next to your 1 key and above your tab key). If it doesn't, you'll want to fix that. The console gives you access to various CS commands and variables, and is required for scripting fun.
First, add -console to your command line. If that doesn't work, open up config.cfg in your cstrike directory with Notepad. Add the following lines to the very bottom of the file and save it.