1. Write out your script.
2. Go to stock.xchng and find a number of free images that match your script.
3. Open up Keynote, select the white theme and delete the text boxes.
4. Open up text boxes and start copying your script. Have the text transition in from right to left. Wherever artistic to do so, add an image from step #2. When you want to make you text slide to the right, select your text box and then click action > move.
5. Check your work with the Keynote play button frequently. You will likely have to change the order and timing of your transitions quite often.
6. To make the older bride picture, I used stock.xchng to find a picture of an older woman. Then I used GIMP to replace the head of the bride. I made the younger bride leave with a disappear transition. I made the older bride appear with an appear transition.
7. To make the Keynote slideshow most efficiently, it is best to create a number of slides. When you create a new slide, you want the title and certain graphics to show up in the same location and in the same size. So, Cmd C to copy them into your clipboard and Cmd V to paste them into the top of your new slide.
8. To make the arrow pointing to the head of the older woman I used the annotations feature. This is how you make the arrow flash on and off:
You will see a new clip on the timeline that represents the arrow. Use the button below the timeline to temporarily increase the width of the arrow clip. Split the clip so that there are four tiny clips. Drag them apart so that there is a space between the each set of tiny clips.