To find resources on the Second Vatican Council in the catalog, select the "Subject" search on the Advanced Search page. Some of the terms you would use include "Vatican," "council," and "Catholic Church - History."
Depending on your topic, you can narrow down your searching even further by adding subdivisions. You could also change the results by the format of the book, adding terms like "Encyclopedias," "Handbooks, manuals, etc.," and "Dictionaries" to the end, bringing back just those types of items.
Broadening your search could be beneficial as well, including searches on "dogma," "liturgy," and "First Vatican Council."
Here are a few examples of some subjects worth searching on this topic:
BX800-839- Catholic Church - Societies, councils, congresses, etc.
BX940-1745- Catholic Church - History
BX1970-2175- Catholic Church - Liturgy and ritual
History of Vatican II by 
A Brief History of Vatican II by 
Modern Catholicism: Vatican II and After by 
From Trent to Vatican II by 
What Happened at Vatican II by 
Roman Catholicism after Vatican II by 
Vatican Council II by 
Vatican II: We've Only Just Begun by 
Reliving Vatican II by 
John Paul II and the Legacy of Dignitatis Humanae by 
