How do you make it.
Plz give me a full tutorial.

First of all, if you haven't already, download this program.

Open that program and select the demo you need as an AVI. Select the 'extract to bmp' function, and play the demo. This will extract the demo frames as pictures in soldat/demos/extracted. WARNING: Only attempt this if you have a fairly good CPU else it will slow it down horrendously.

Once you have done that you can download a program (search Google) to compile multiple pictures into an AVI file.

Alternatively, you can just record your Soldat games with FRAPS which automatically makes AVIs.

The CPU would be less of a problem.. your hard disk has to write lots of data, because bitmaps are uncompressed (640*480 BMP = 900kb each)
I'd use Fraps..

http://selfkill.com/webv3/content/cms.php?action=showdetails&id=209&title=Frequently%20Asked%20Questions
a little tutorial about movie making in Soldat
just play your demo (don't ask how to..) and record it with Fraps. Yes, I know, this will lag and YES, the file will be very large. Now get a nice codec like DivX or XviD (google) and compress the movie.

thx