Then: the connecting word here simply introduces the next in the series of events.

Blew the trumpet: it is doubtful that Joab himself blew the trumpet. Probably he simply gave the order that the trumpet should be blown. For this reason Good News Translation has translated “had the trumpet blown.” On the word for trumpet, see 2.28; 6.15; 15.10; 1 Sam 13.3.

Came back from pursuing: it may be more natural in certain languages to say something like “stopped chasing” or “ceased fighting.”

For Joab restrained them: this indicates the purpose of blowing the trumpet. In some languages it will be more natural to make this a part of the sentence about blowing the trumpet, rather than a separate sentence as in Revised Standard Version. Two possible models are “in order to inform the soldiers to finish…” and “to signal his troops to stop…” (Contemporary English Version)

As often in 1 and 2 Samuel, the Hebrew uses the word “people” in reference to the troops. The Hebrew says “… and the people came back” and “for Joab restrained the people.”

Quoted with permission from Omanson, Roger L. and Ellington, John E. A Handbook on the First and Second Books of Samuel, Volume 2. (UBS Helps for Translators). New York: UBS, 2001. For this and other handbooks for translators see here .