I think he's talking about rendering? Can't tell.
If so, when your done rotoscoping and the video looks the way you want it to, then click on "render" in the top menu. You'll want to check your "render settings..." to make sure your video is being exported in the format you want. Check out Axeman's tutorial
on how to retain your sound if you wish to do that. After you've checked your settings and made sure everything is good, click the render menu button again and press the "render" option and your video will be exported to your chosen location.
Edit: Or you can check out Tarn's tutorials by clicking "Support" at the top of the page.