You can choose whether or not to include this slide in the slideshow by checking or unchecking the Include In Slideshow checkbox.

Also, the Show Slide For edit box can be used to specify exactly how many seconds the slide should remain up before switching to the next slide. Note that for complicated slides or for large bitmaps, the minimum will be bounded by how long it takes to generate the next slide. You can also specify fractions of seconds. A value of 0 causes the slideshow not to advance until the mouse button / spacebar / ctrl + right arrow key is pressed.