Here Yahweh speaks of Moses giving some of his authority to Joshua as if it were an article of clothing that he could put on him. AT: "You should give him some of your authority" or "Let him decide what the people should do" (See: [[rc://en/ta/man/translate/figs-metaphor]])
This was a sacred stone that the High Priest wore on his chest plate. He used it to determine God's will. (See: [[rc://en/ta/man/translate/translate-unknown]])
This means that Joshua will have authority to command the movements of the community of Israel. "Going out" and "coming in" are two opposite commands used to emphasize that he will have full command over their movements. AT: "He will command the community's movements" (See: [[rc://en/ta/man/translate/figs-merism]])
Both of these phrases mean the same thing, and they are used together for emphasis. AT: "both he and the entire nation of Israel" (See: [[rc://en/ta/man/translate/figs-parallelism]])