Ground Floor: Community
The ground floor is where people get connected to the parish community. Not the programs, the people. You can't have a parish without one, because God didn't save us as individuals. He saves us by gathering us into a Church.
A lot of devout Catholics resist this floor. The church is not a social club, they say, and they're right. But it does need social elements, because those elements are the ground God plants the seed of faith in. This floor is on the ground for a reason: it's the earthly, human aspect of the Church.
First Floor: Conversion
The first floor is where people actually meet Jesus. That takes more than an hour, and it takes getting away from ordinary life. Jesus went into the wilderness for forty days before He preached a word. The Catechism calls the liturgy the privileged place for catechizing the People of God. It's not the primarily place for evangelizing, it assumes the encounter has already happened. Something has to come first: retreats, missions, pilgrimages, etc. whatever creates the space where a person can hear God and answer Him.
Second Floor: Catechesis
The second floor is where people learn what the Church actually teaches, and why.
Tradition means "handing on" and Catechesis is the act of handing on the fullness of the faith from one generation to the next: the Creed, the Sacraments, the moral life, prayer. The problem is you can't hand on something you never received, and most Catholics stopped receiving it around eighth grade. This floor fixes that problem.
Third Floor: Commission
The third floor is the parish turned outward and fulfilling the Great Commission.
A parish is not the walls of the building. A parish is a geographic boundary, and everyone living in it. The mission statement of the Church is: Make disciples of all nations. The Church has divided those nations into parishes, so your mission statement is "Make disicples of your whole town."
Everything below this floor was building toward this mission. The ground floor gives them a home to belong to, the first floor helps them meet Jesus, and the second floor helps them learn the Faith. The third floor teaches people to go find new people and bring them through the floors.