Libre Impress is the presentation software, part of the LibreOffice bundle. It is an open-source alternative for MS PowerPoint.

If you are aware of creating presentations using PowerPoint, you will be able to work with the interface of Libre Impress. Libre Impress is used in a few companies, especially start-ups that do not heavily depend on paid proprietary software.

To know more about Libre Impress, refer http://www.libreoffice.org/discover/impress/.