"after a day's walk." A day's journey is the distance that people would normally travel in one day. This can be translated "after Jonah walked for one day."
## from the greatest of them down to the least of them ##
"So everyone, including all the important people and all the unimportant people" (UDB)
## They all put on sackcloth ##
The reason that they put on sackcloth can be made explicit: "They also put on coarse cloth, to show that they were sorry for having sinned." (UDB) (See: [[rc://en/ta/man/translate/figs-explicit]])