From the “Ceremonial for Bishops” (this work along with the “General Instruction of the Roman Missal” contain the official liturgical norms for the Church, along with the Roman Missal, Lectionary etc):
Reverence toward the Blessed Sacrament
norm 71. No one who enters a church should fail to adore the Blessed Sacrament, either by visiting the Blessed Sacrament chapel or at least by genuflecting.
Similarly, those who pass before the Blessed Sacrament genuflect except when they are walking in procession.
A
genuflection, made by bending only the right knee to the ground, signifies adoration, and is therefore reserved for the Blessed Sacrament, whether exposed or reserved in the tabernacle, and for the holy cross from the time of the solemn adoration in the liturgical celebration of Good Friday until the beginning of the Easter Vigil.
Neither a genuflection nor a deep bow is made by those who are carrying articles used in a celebration, for example, the cross, candlesticks, the Book of the Gospels.
Reverence toward the altar
norm 72. A deep bow is made to the altar by all who enter the sanctuary, leave it, or pass before the altar.
A
bow signifies reverence and honor toward persons or toward objects that represent persons.
There are two kinds of bows, a bow of the head and a bow of the body:
a. a bow of the head is made at the name of Jesus, the Blessed Virgin Mary, and the saint in whose honor the Mass or the liturgy of the hours is being celebrated;
b. a bow of the body, or a deep bow, is made: to the altar if there is no tabernacle with the Blessed Sacrament on the altar; to the bishop, before and after incensation; whenever it is expressly called for by the rubrics of the various liturgical books.
https://www.amazon.com/Ceremonial-B...s=Ceremonial+of+Bishops&qid=1592366870&sr=8-1
https://www.amazon.com/General-Inst...92367048&sprefix=general+instr,aps,443&sr=8-1