The Eucharist is indeed the source and summit of the Christian life - in the Eucharist, Jesus Christ enters into us under the humble species of bread and wine. We receive this Divine Life through the regular and worthy reception of this great Sacrament - meaning we participate in the Holy Mass weekly, and receive the Sacrament of Reconciliation regularly (especially if we have committed a mortal sin, in which case the Eucharist should not be received until we go to Confession).
For information about 1st Communion, see the 2nd Grade Sacraments page.
Still, many questions about the Church's teachings on the Eucharist still exist. This short video answers some of them.