What does some of the symbolism of the wedding traditions mean: white, rings, altar, vows, etc?

White: White is a symbol of purity, innocence, joy, and celebration. In the Christian tradition, white is the symbol of holiness, so much so that the early Christians believed that white repelled the devil.
Rings: Rings have symbolism beyond the wedding. But within the boundaries of wedding symbolism the circle means eternity and unity. It represents the unending state of matrimony — a “forever until death do us part” association. The ring has traditionally stood for a covenant or agreement, or the seal of a binding contract. More specifically, the ring represents the marriage vow. Two rings joined together are a symbol of joint covenant, unity, and united love or life.
Altar: The altar is the center and focal point of a church, where the sacrifice of Christ on the Cross is made present under sacramental signs in the Mass. It represents the mystery of the Eucharist. (Catechism of the Catholic Church glossary). The Eucharist is the source and summit of the Christian faith as well as the source and focal point of all the other sacraments of which Marriage is one.
Vows: Vows are promises made by the man and woman before God and the priest or deacon as a representative of the Church. The couple publicly declares their love for each other. They promise each other permanent and faithful love. They promise each other fruitful love and openness to life that images God’s love. Living the vows is ongoing, living proof of their love for each other.
Blessed Mother Flowers: While it is not part of the Marriage Rite, couples may present flowers to Mary after the closing prayer, as a sign of love and devotion. Mary is the model of discipleship and obedience to God for all believers. Christian spouses can follow Mary’s example of faith and trust. Husbands and wives can look to Mary, Virgin and Mother, as a model of marital chastity and fidelity. Married couples, in particular, can seek her intercession with her son Jesus, knowing that she understands both the joys and sorrows of married life and parenthood.