Bow to the altar, kneel to the Blessed Sacrament.
Once upon a time, the Blessed Sacrament (the consecrated altar bread, that is, Our Lord, Body and Blood, Soul and Divinity) was kept in a box, known as a Tabernacle, at the back of the main altar in the church. After Vatican II, they moved the Blessed Sacrament to a side chapel.
So now Catholics look around when they enter a church. If you see a red lamp burning, that indicates that the Blessed Sacrament is present, and you genuflect (”curtsey”) in that direction. If there’s no lamp and no tabernacle, then you bow to the altar, which is front and center in the church.
The Priest dips the altar bread in the wine, right? For years I thought that the Priest was hoggin all of the wine, cuz I never saw any individual little glasses like I was used to seeing.