About slide animation timings (from Microsoft PowerPoint Help)  

When you add animations  to your slides, you have a variety of timing options available to ensure that every piece flows smoothly and looks professional. Set up your custom animations or adjust the preset animation schemes  you have applied with options for start times (including delays), triggers , speed or duration, looping (repeating), and automatic rewind.

Custom Animation listview with timeline

Callout 1 Title of animated item, based on text used on the slide.

Callout 2 Time blocks and moving timeline; only visible when you preview animations.

Callout 3 Indicates seconds and includes zooming options and a scrollbar; only visible when Advanced Timeline is shown.

You can change the order of an animation or groups of animation sequences by selecting the item in the Custom Animation list  and dragging it to a new location in the list. The expand or collapse arrows let you see sequences within each item and move them within or outside of the item. The arrow on a selected list item displays a menu with options such as Timing and Effects. When you preview animations on the slide, a small timeline appears at the bottom of the Custom Animation task pane , illustrating the timing for each animation in seconds.

The Advanced Timeline looks almost the same as the timeline you see when you preview animations. It allows you to edit relative timings for animations by selecting the item from the Custom Animation list and then dragging the timeline marker.

Custom Animation advanced timeline

Callout 1 Timeline marker, which only appears with the Advanced Timeline.

Change timings for animations (from Microsoft PowerPoint Help)  
  1. If the Custom Animation task pane (task pane: A window within an Office application that provides commonly used commands. Its location and small size allow you to use these commands while still working on your files.) is not displayed, on the Slide Show menu, click Custom Animation.
  2. In the Custom Animation task pane, click the item in the Custom Animation list (Custom Animation list: The list of animation sequences for a slide. Items are listed in the order in which they are added, and include icons that indicate timing in relation to other animation events.) that you want to change the timings for.
  3. Click the arrow, click Timing, and then do one or more of the following:

    HideChange start time in relation to other animations on the slide

    1. If you want to create a delay between the end of one animation and the start of the next item in the list, click an option in the Delay list.
    2. In the Start list, do one of the following:
      • If you want to start the animation by clicking the slide, click On Click Button image.
      • If you want to start the animation at the same time as the previous animation in the list, click With previous.
      • If you want to start the animation right after the previous animation in the list finishes, click After previous Button image.

        If this is the first animation on the slide, it will be marked as "0" and will start as soon as the slide appears in the slide show.

    Note  You can change the order of animations on a slide by selecting the text item or object in the Custom Animation list and then dragging it to a new location in the list.

    HideChange timings for animated paragraphs or bullets

    1. On the Text Animation tab, do one of the following:
      • If you want the paragraphs to play each on separate click of the slide, clear the Automatically after n seconds check box.
      • If you want the paragraphs to play consecutively after one click of the slide, select the Automatically after n seconds check box and type a number in the box if you want to delay the start of the animation between paragraphs.
      • If you want all paragraphs to animate at the same time, in the Group text box, select All paragraphs at once, and clear the Automatically after n seconds check box.

    Note  This works only for animations that have been applied to a text placeholder (placeholders: Boxes with dotted or hatch-marked borders that are part of most slide layouts. These boxes hold title and body text or objects such as charts, tables, and pictures.) and contain 2 or more paragraphs (including bullets).

    HideSet an animation to play when the text or object is clicked

    1. Click the Triggers button.
    2. Select the Start effect on click of option.
    3. Select an item from the list.

    HideChange speed or duration of the animation

    • Click an option in the Speed or Duration list.

    Note  This option is dependent on the animation you choose.

    HideLoop an animation

    • Click an option in the Repeat list.

    HideAutomatically rewind an animation after it plays

    • Select the Rewind when done playing check box.

    Note With this option selected, the animated item will return to its original state. For instance, if you apply the Fly out effect, the item will fly out, but then will reappear on the slide in its original location.