I expect that the sort of bread involved is determined by the pastor’s preference (or deacon, or secretary, or whoever bought the stuff), or else availability. The Bible just says “bread,” though I suppose that we could infer that it was indeed matzot, since the Last Supper was on Passover, and there are Rules about what bread ought to be like on Passover. That way, though, lies the potential for excessive legalism.
The actual method for administering the wine/grape juice varies: there’s the little cup sorts (good for large congregations), the communal cup (typically used with actual wine, which may be alcoholic enough to have disinfectant properties), and in some churches, the congregants will dip their bit of bread into a common cup. I am sure that there are others.
Don’t worry about the potential for sacrilege: Jesus Himself lays out the template for communion, in Matthew, I think. The practice is strictly commemorative (except, I think, for Catholics; for them, the host is on some level actually transmuted into the body of Christ); it refers the partakers to Jesus’ crucifixion, a sacrifice to atone for the sins of all mankind.
Try thinking of it in terms of mankind’s relationship with bread. Bread is a staple that much of the world depends on for its sustenance, to the point that it gets used to represent food in general. In this way, Jesus is like bread: a provider of spiritual sustenance. Life, even.
It’s a slightly convoluted simile.
There. Hopefully, I haven’t wandered inadvertently into heresy.