The Lord said to Moses: Make two trumpets out of embossed silver and use them to summon the congregation and when you must start off with the camps. If you blow both of them to the whole congregation, they shall gather before the door of the tabernacle. If you blow only one, then just the princes shall gather.

But if it is blown loud, the camp shall go forward and lay to the east. But if you blow loud the second time, the camp shall go south.But when the congregation shall gather, you shall only blow the trumpets and not play it too hard.
However, the priests, the sons of Aaron shall blow the trumpets as the only order for you and your descendants.

If you go to war against your enemies, then you shall sound the trumpets out loud and be saved by your friends. Likewise, when you are happy at your feasts and new moons, burnt offerings and thanks offerings.