Numbers 10:7 New English Translation

⁷But when you assemble the community,^[a] you must blow the trumpets,^[b] but you must not sound an alarm.^[c]

Numbers 10:7 tn There is no expressed subject in the initial temporal clause. It simply says, “and in the assembling the assembly.” But since the next verb is the second person of the verb, that may be taken as the intended subject here.
Numbers 10:7 tn Heb “blow”; the direct object (“trumpets”) has been supplied in the translation for clarity.
Numbers 10:7 sn The signal for moving camp was apparently different in tone and may have been sharper notes or a different sequence. It was in some way distinguishable.

New English Translation (NET)