The default duration of titles is set in preferences. However, normally you will have different lengths for different situations. Once you have done your title, it appears like a brief video clip in the Title band of the timeline. If you click on it, it will show yellow borders, with a heavy yellow bar at the right and left hand ends. To change the length of the title is simple. Left click either the left or right hand bar and hold the mouse button down while you drag the bar either left or right to shorten or length of the duration of the title. The alternative, to set an exact time is to use the little clock on the Edit tab to the right of the preview screen, about half way down the screen. The first thing in that Edit tab is the clock and you can set exact figures. Note that it is divided into hours : minutes : seconds : frames.
As you may have already found, you can change font, colour, etc in that Edit tab. Beside it is an Attribute tab. If you have the title appearing on the preview screen, then the first button on the Attribute tab (Animation) is by default selected (solid white). If it isn't, then simply click it to select it. Then, make sure the next little box down (Apply) is ticked. To its immediate right is a drop down menu window and when you click on that, you are given the choice of various animations. Fade is amongst them, so select it.
Now to the immediate right of that drop down window is a double letter T. That allows you to alter how the fade appears: it allows you to fade in, fade out or have a cross fade. And it allows you to change the duration of how long the title appears solid before fading in or out.
Good luck!!
