Thanks for writing. If you have an established clivia, you can dig it up and divide the clump. Get more information on dividing here: http://www.bhg.com/gardening/dividing-perennials/
You can also collect seeds from your clivia and grow them. Seeds germinate best in spring, but require a little patience: The plants can take 4 or so years to bloom from seed.
---Justin, Senior Garden Editor, BHG.com