In the 2nd Eucharistic Prayer, we ask the Holy Spirit to come down on the gifts of bread & wine like "dewfall." This image comes from the Old Testament reading from Exodus today. The people in the desert were hungry in their long journey. So God sent them bread from heaven. How? In the morning, under the dewfall (the moisture from the cold night air), they found white flakes of a substance they could gather in order to make bread. God fed them through this manna (bread) in the desert.
At Mass, we too ask the Holy Spirit to come down upon the gifts of brad & wine like dewfall, so that we may be fed with the Body & Blood of Jesus. The Spirit feeds us.
I recently received an elderly woman into the Catholic Faith. She is under the care of Hospice. Her joy at being given the Bread of Life (the Eucharist) was palpable. She is at peace. That is the what the Spirit does. The Spirit feeds us with bread from heaven to keep us nourished in our faith.