At Confirmation we receive the gifts of the Holy Spirit and we confirm the promises we made, or which were made on our behalf, at our baptism. Confirmation is normally celebrated by the bishop who lays hands on the candidate and anoits their head with a holy oil called Chrism.
Bound more intimately to the Church by the sacrament of confirmation, [the baptized] are endowed by the Holy Spirit with special strength; hence they are more strictly obliged to spread and defend the faith both by word and by deed as true witnesses of Christ.
In the Acts of the Apostles, we read about the Holy Spirit coming upon Jesus's disciples at Pentecost. In baptism we are born again into the new life of Christ, Confirmation deepens that new life within us. Baptism makes us members of the Chruch, the Body of Christ, Confirmation strengthens those bonds and fills us with the Holy Spirit that we may minister in the world and proclaim the Good News to all nations.
After they had received the Holy Spirit at Pentecost, the apostles went out and confimed others, laying hands on them and filling them with the gifts of the Holy Spirit.