Numbers 33 is a recounting of the Israelites' journeys during their 40 years of wandering in the wilderness after the Exodus from Egypt. Verse 13, "They traveled from Dophkah, and encamped in Alush," simply means:

They traveled: The Israelites, as a large group, moved.
from Dophkah: They departed from a place named Dophkah, where they had previously set up camp.
and encamped in Alush: They set up camp in a new location called Alush.

In essence, it's a record of a stop in their itinerary. It provides a geographical marker in their long journey.

Significance:

Part of a larger historical record: This verse is part of a comprehensive list documenting the various stages of the Israelites' arduous journey.
Geographical clues (though sometimes uncertain): While the exact locations of Dophkah and Alush are not definitively known today, they were real places significant to the Israelites' experience.
Reminder of God's faithfulness (and the Israelites' trials): The detailed listing serves as a reminder of God's provision and guidance during their difficult period of wandering and of the difficulties and challenges faced by the Israelites.

Without more context, the verse itself is a simple statement of a movement from one place to another. The bigger picture is the overall narrative of the Exodus and wilderness wanderings.