Why do you use candles in broad daylight, and what is the 'golden box' up front?
Thankfully, we now have electricity and do not have to rely on candles to see as did the early Church. However, candles still symbolize the light of Christ in our presence and serve as a reminder that we too, are called to be a light to the world.
You may notice that there are two candles on the altar and six on the stone mantle behind the altar. The type of service dictates which candles are lit.
The candles on the altar are lit when the altar is used, namely for Communion. The candles on the mantle, behind the altar, are lit at all times, even for non Eucharistic services. They are often called the Office Candles, and lit during the daily offices of Morning and Evening Prayer. All candles are lit for a primary service or high mass. For low mass, or weekday services, only the candles on the altar are used.
The 'gold box' is called either the tabernacle or the aumbry. It derives its name and symbolism from the Book of Exodus, wherein the Lord dwelt among His people. The word tabernacle means literally to dwell. And as you may recall, the Lord would appear in the tent of meeting with Moses in the form of a cloud descended upon the earth. With the coming of Jesus, God dwelt among men once more.
Yet, even after his resurrection to His rightful place alongside God the Father, He dwells in us through the Holy Spirit. Likewise, He is present in the tabernacle where we reserve the consecrated bread, the Body of Christ. In doing so, God tabernacles with us. When the Sacrament is reserved the sanctuary candle is lit (the hanging candle), and serves to remind us that Christ is indeed physically present among us.
Each aspect of the church has a meaning, so keep an 'eye out' for what is to come next week!