how to work offline

See Deploying charmed operators offline. The exemplar snap for Juju users is charmed Operator Tools but the guidance provided here can be applied to any snap. See Installing snaps offline.

Those two links are 404 Not Found as well. Can I know the method above

Many docs for juju are written in discourse then published here: https://juju.is/docs/juju.

The links provided are purposefully archived. The official location for the information you’re looking for starts here: https://juju.is/docs/juju/working-offline