Effects must be added to the Timeline before you can start working with them. Effects can be added to either or both the video tracks. Effects are represented on the effect track that accompanies every video track (Video 1 and Video 2).
Read the article on Applying Effects Correctly.
There are several ways to add an effect to a video track. You can:
You can also:
The effect will be added to the selected effect track at the Seek Slider position. If the Seek Slider is positioned on or before an existing effect, then the selected effect is added at the end of all the existing effects in the same track, instead of the slider position. By default, an effect of ten-second duration is added to the Timeline that can be later resized to the desired duration.
You may also add an effect by dragging and dropping it from the Video Effects list to the Effect track you want. The seek slider moves to the position where you drop the effect.
The default duration of the effect can be changed. Select Options from the Tools menu and select Source Settings and change the duration for effects.