Q. How do I cite the catechism in APA? I have the link attached I am using?

This is a bit of a mess for citing. It looks like the Vatican took a square peg (the orginal print Catechism) and tried to squish it into a round hole (an online site). It ends up missing parts and sometimes, when trying to determine what the title of the entry is, especially with the chapter headings, it becomes a mess.

We can probably use the form for an online reference book and do our best with it. Here it is from p. 16 of APA Style Guide to Electronic Resources, 6th edition.

Chapter in a book or entry in a reference book

Author, A. A., Author, B. B., & Author, C. C. (year). Title of chapter or entry. In A. A. Editor & B. B. Editor (Eds.), Title of book (pp. xxx–xxx). Retrieved from http://xxxxx

Normally, you should not assume authorship, but since this is off the Vatican website, we will credit it to the Catholic Church. So, with the pieces we have, we can cobble together a citation that looks like this -

Catholic Church. (n.d.). The dignity of the human person. In Catechism of the Catholic Church. Retrieved from 

     http://www.vatican.va/archive/ccc_css/archive/catechism/p3s1c1.htm

Because the URL takes us directly to the section you are using, I don't think we need to worry about the section and chapter number. I think this fits the spirit of the law and should work.