Judas and his soldiers began the battle, so translators should start a new paragraph here (so Good News Bible, Contemporary English Version).

Then he came up behind them in three companies: Companies are groups of soldiers in battle formations. “Columns” (Good News Bible) is a modern equivalent. “Groups” will be sufficient. So for this clause we may say “Judas divided his army into three groups to attack the enemy from the rear [or, from behind].”

Who sounded their trumpets and cried aloud in prayer: Sounded their trumpets may be rendered “blew their trumpets” in many languages. Cried aloud in prayer may be expressed as “shouted prayers” (Good News Bible, Contemporary English Version) or “shouted as they prayed.” Translators should consider joining the last half of this verse to the next verse (see the model below).

Quoted with permission from Bullard, Roger A. and Hatton, Howard A. A Handbook on 1-2 Maccabees. (UBS Helps for Translators). New York: UBS, 2011. For this and other handbooks for translators see here.