Explanations

ADVENT= The coming or arrival, especially of something extremely important (e.g. "this is the advent of a new era"). The liturgical period preceding Christmas, beginning in Western churches on the fourth Sunday before Christmas, a period to prepare Christians for the arrival of Christmas celebration.

MEDIEVAL TIMES= The Middle Ages, the time in Western history between the fall of the Roman Empire and Renaissance (centuries 8th to 14th, more or less).

DRAMAS= Theatrical performances.

FEATURED= If a play, TV show, movie or another kind of show features a person or something, that person, thing or event is there.

EVERGREEN= An evergreen plant keeps its leaves all through the year (as opposed to other plants which lose their leaves in autumn and winter).

THE TREE OF LIFE= You need a bit of Christian theology to understand all this:
The first book of the Bible is called GENESIS, and it tells about the creation of the world and of people. According to this story, God created a man called ADAM and a woman called EVE (the first people), and they lived in the Garden of Eden, a paradise where they were happy and they had no need to work. They could do anything they wanted, except one thing: they couldn’t eat the fruit of the TREE OF LIFE, which was an apple tree planted in the middle of Paradise. Finally, the Devil made them eat the apple (the forbidden fruit) and so they sinned and they were expelled from Paradise. Some Christians think this really happened, but most Christians consider it a metaphor to explain spiritual facts (God created everything to be in harmony, but sin breaks that harmony and all suffering comes from sin). Anyway, Jesus saved people and opened the doors of heaven to them (an afterlife Paradise and the promise of a better society on earth: the Kingdom of God). Most Christians (Catholic and Orthodox churches) believe that Jesus is really present in the host (a consecrated bread they eat in mass). So that host (bread) is the opposite of the apple from the Tree of Life, because the apple sent people out of Paradise and the host is opening the doors of Paradise again.

FIR TREE= An evergreen tree similar to a pine (see picture here).

WAFERS= A small thin crisp cake, biscuit, or candy (see picture here).

HOST= Consecrated bread used in Christian mass (see picture here).

EDIBLE= Something edible can be eaten.

INFANT= A child in the earliest period of life, especially before he or she can walk.

MESSIAH= A Hebrew word pronounced /məsaɪə/. One who is anticipated as, regarded as, or professes to be a saviour or liberator. In the Bible, God promised to send a messiah to save people from their sufferings. Christians believe Jesus is that messiah and called him the Christ (which is a Greek word which means "messiah").