This speaks of years as if they are something that travels and comes to a place. Alternate translation: "during the good years that will soon happen" (See: [[rc://en/ta/man/translate/figs-metaphor]])
The phrase "under the authority of Pharaoh" means Pharaoh gives them authority. Alternate translation: "use the authority of Pharaoh to store the grain" (See: [[rc://en/ta/man/translate/figs-idiom]])
The word "they" refers to the overseers and represents the soldiers that they should command to guard the grain. Alternate translation: "The overseers should leave soldiers there to guard the grain" (See: [[rc://en/ta/man/translate/figs-metonymy]])