ahh hell Ill type it out Im bored:
To record a demo:
Simply type record <demoname>
So let's so you want to record a demo of a scrim, here's the simple way
record scrim1
to end the demo exit CZ or just type end
To play a demo:
there are manythings you can type to view it, to view the demo well, with good framerate and such type: playdemo <demoname>
so if you want to view the scrim demo that you just recorded type: playdemo scrim1
The location of your demo's:
the exact location is:
c://programfiles/valve/steam/steamapps/ ... zero/czero
The file name will be exactly what the demo name is "scrim1, scrim2, etc"
To show other people your demo's:
Find the demo you want to show
Send to them over aim, use a file hosting server to send it online "fttp, fileplanet, rapidshare etc" If some one wants to send you a scrim, simply go save it to your desktop, and move the file into the czero folder mentioned above!
Your screen shots are also in your czero folder.
Any more questions and i will be happy to answer them for you!
EDIT: Dang you oce beat me to it..well I actually typed mine out =P