Hello there, caltu.
The following Keynote Help for Mac document provides some great information in the "Animate Objects" section which you can type into the search field to locate:
Animate objects - Keynote Help for Mac
https://help.apple.com/keynote/mac/6.2/#/tan72234bb6
To make your presentation more dynamic, you can animate the objects on a slide. For example, you can make text appear on the slide one bullet point at a time, or make an image of a ball bounce onto the slide.
Object animations are called build effects. Different build effects are available depending on whether the object is a text box, chart, table, shape, or image.
Moving an object onto a slide is building in. Moving an object off a slide is building out. Moving an object around on a slide is an action build.
The different ways to accomplish this will be listed below that text.
Thanks for reaching out to Apple Support Communities.
Cheers,
Pedro.