I'm trying to set up a backup situation where I work with source files in the Lightroom catalog (add,delete,modify)..then have it reflected in a backup ( external drive,cloud backup). Not sure how to do this ?
What version of Lightroom are you using? Lightroom Classic uses a catalog, and the edits are stored in that catalog. That means you should make a regular backup of the catalog, and Lightroom Classic has built-in options to do just that. Lightroom (cloud) stores everything in the cloud. You cannot really make a local backup.