You should use the settings (the little gear icon to the left of the record icon) to set your capture framerate to a minimum of 30, frame quality to 100 (95 is default), and possibly turn off capturing your mouse before beginning. Encoder Screen Capture also gives you a 3 second countdown to allow you a little time to compose yourself before recording kicks in. There is integrated support for recording voice and|or a webcam at the same time, if you so choose, or neither, if you would rather leave the talking to what you'll be saying onstage.
Once you decide you like what you've captured, click the Encoder icon in the lower right hand corner of the capture-review player and it will ask you for a place to save your recorded inputs in Encoder Project format. When this is done Encoder will automatically launch with your video ready for encoding to a final wmv (or mp4 if you've got the full version) output.