First you will need to download the following files,
Windows Movie Maker and of corse Reyks new triggers

Open the Scenario you want to "capture" a bit of. Then Insert the following trigger in.
Name: Sceenshot_trigger_take
_{Trigger:Loop
Condition:Timer ms; 100ms
Effect:Screenshot}

^^How Your trigger box should look^^

Use the fire event trigger to start the trigger when you want to, if you are in a cinematic and cant exit once you have "captured" the bit you want to, use this trigger.
Name:Screenshot_trigger_stop
_{Trigger:active
Condition:Abort Cinematic
Effect:Disable Trigger; Sceenshot_trigger_take}

^^How Your trigger box should look^^

Now playtest the scenario and it should start taking screenshots at a rate of one every tenth of a second. When you've "captured" the scene you want to, either quit (or in the case of a cinematic, press the space bar).

Now load up Windows Movie Maker, you should come up with a screen looking like this

Now click on File, Import

^^Could I make it more clearer^^

Next open your screenshots folder and find the sceenshots which "capture" what you wanted, eg if my screens were screen240 through to screen 250 then my screen would look like this

^^How My Screen Would Look^^

Click open and Windows Movie Maker will import your files and your screen will look like this

^^How your screen should look (the pictures will be different)^^

If at this point the bottom bit of your screen looks like this click on show timeline

Click and drag all your screenshots into the bar named Video and your screen should look like this.

^^You will have more screenshots^^

Click on the zoom in button as many times as you can

^^The Zoom in button^^

Your pictures should now be really long, click on the little arrow at the side and make the picture as short as you can, do this for all of them.

^^The Little Arrow(you need to click on the picture to get the arrow up)^^

There is your movie, press play and sitback and watch your handiwork.

^^Thats it your movies done^^

To export as a WMV file click file, save movie file,

^^Windows Movie Maker's Version of the export button^^

Then a box like this should come up

^^What the box should look like^^

Make sure my computer is selected, and then click next. This box should then come up.

^^The next box^^

Simply enter the name of your film, and where you want to save it and click next.

^^The final Box^^

Click show more choices and select other settings and choose the quality that best suits the use you have for it. (Lower quality for internet use)

It will then save the movie.

There You have it, A guide for making WMV trailers for your campaign.

(comments please people this is my first guide)