Prefer to read? Start here:
A Popular Guide Based on The Catechism of the Catholic Church
by John A. Hardon, S.J.
You can also study any aspect of the Catholic Faith (by topic) explained by master catechist Father John Hardon, S.J.
Prefer to Listen?
Here are some great resources for learning the Catholic Faith
Prefer to Watch?
Here are some great video resources for learning the Catholic Faith
The Institute of Catholic Culture