This is the burnt offering of every sabbath refers to the two male lambs in the previous verse. For burnt offering (ʿolah in Hebrew), see verse 3.

Besides the continual burnt offering and its drink offering: New Living Translation makes it more explicit that this weekly burnt offering had to be offered “in addition to the regular burnt offering and its accompanying liquid offering” (similarly Good News Translation, Bible en français courant). The continual burnt offering refers to the two daily burnt offerings (verses 3-8). The pronoun its refers to these daily offerings (so Levine, page 376), which each had an accompanying drink offering (verses 7-8). The Hebrew pronoun for its and the word for burnt offering are both feminine.

Quoted with permission from de Regt, Lénart J. and Wendland, Ernst R. A Handbook on Numbers. (UBS Helps for Translators). Miami: UBS, 2016. For this and other handbooks for translators see here .