Three things need to be backed up:
- the LR catalog
- the LR support files like the develop presets
- your images
Lightroom does the catalog backups for you. See the Catalog Preferences dialog for the scheduling. The important thing that you need to do is to make sure that the catalog and its backups are on different drives (by default LR puts them on the same drive) so that a single drive failure does not take the backups and the catalog with it.
A restore of the catalog is done by copying the backup to the original catalog location and unzipping the catalog. Never use a catalog directly in the backup folder.
It is up to you to backup the support files and your images. This can be done with anything from a simple copy-paste using Finder/Explorer to a true backup software. Personally, I use a simple batch script to copy new files to an external hard drive.
Thanks so much.