# before Yahweh

Possible meanings are 1) "in obedience to Yahweh" or 2) "in front of Yahweh's ark" 

# they gave a blast on the trumpets

"they sounded the trumpets loudly" or "the priests blew into the ram's horn trumpets"

# The ark of the covenant of Yahweh followed after them

"The priests who were carrying the ark of the covenant of Yahweh followed after them"