Shulchan Arukh, Orach Chayim 260/שולחן ערוך·אורח חיים ר״ס

1Laws Governing [Preparations for] the Onset of Shabbos, 2 Seifim: It is a mitzvah to wash Rema: one's whole body. If it is not possible he should wash (Tur) his face, hands and legs with warm water on Erev Shabbat. It is a mitzvah to wash one’s head and trim one’s nails every Friday. Rema: If one’s hair [has grown] too long, it is a mitzvah for him to cut it. And when one trims one's nails one should not grab hold of them in order. One should begin trimming the nails of his left hand with [those of] the kami­tzah, (i.e., the fourth finger, the one next to the pinky). On the right hand, [one should start] with the index finger, the second finger, the one next to the thumb. Thus, a memory cue for the order is בדאג"ה (2, 4, 1, 3, 5) on the right hand and דבהג"א (4, 2, 5, 3, 1) on the left. (Avudraham in the Sefer HaMussar)

2When it is close to nightfall, one asks of the members of his household in a gentle tone, have you tithed? Have you established the Eruv? Have you separated Challah? And he says to them, 'light the candle'. In a place where one does not tithe, it is not necessary to ask if one tithed (Tur)