How does someone join the Catholic Church? 

Through a process called the RCIA. Rite of Christian Initiation of Adults (RCIA) is the process in which adults become full, participating members of the Catholic Church. Participants go through a process of studying the Gospel, nurturing their relationship with God, becoming familiar with the Catholic teachings and practices, and professing their faith in Jesus and the Church. 

There are weekly gathering which starts in October and ends in Easter Vigil.